When I was a boy I lived on the coast, and I went to sleep every night with my mind peacefully roving toward the dark water of the bay. The bay was murky, but in my dreams the water became so clear I could feel my eyes straining from the effort to extend their range, to locate some finite point in that endless crystal void. The creatures I saw gliding about underwater were always mys-teriously benevolent. They were not fish usually, but half-glimpsed amalgams of real and imagined animals, adapted—as I apparently was—for underwater life. They had been waiting for me to appear. The water’s sudden clarity seemed to have roused them, as if until now they had been physically entrapped in their gloomy element like prehistoric animals in a peat bog. I felt released too, beyond the reach of wakeful caution, beyond the jurisdiction of physical laws. I could breathe, I could range wherever my will would take me, soaring along the contours of the sea bottom or spiraling up toward the surface, into the high altitudes of the ocean atmosphere.

All my life I have dreamed one variant or another of that dream. I have had a passion to be underwater. How this passion developed I’m not sure, but I remember the longing I felt—the brutal, unappeasable longing of a very young child—when my mother used to read to me, night after night, a story called The Water Babies.

The Water Babies is a novel for children written in 1862 by a strange, sex-tormented Victorian cleric named Charles Kingsley. According to his biographer, Susan Chitty, Kingsley “could only accept the idea of carnal relations with his wife once he had convinced himself that the body was holy and the act of sex a sacrament in which he was the priest and his partner the victim.” Kingsley sorted through his obsessions by writing verse and best-selling novels and by producing a series of disturbing drawings that depicted him and his wife, Fanny, in rapturous postures of self-mortification—drawings that, in the words of Nathaniel Hawthorne, “no pure man could have made or allowed himself to look at.”

And yet purity was Kingsley’s lifelong ideal. The Water Babies is the story of a poor and abused boy named Tom, whose work as a chimney sweep has left him habitually covered with grime. While servicing the chimneys of a country gentleman’s estate, he finds himself in the presence of a sleeping girl whose angelic cleanliness makes him quake with desire and shame.  When she awakes and sees him by her bed, she screams, and he flees from the house. Finally he comes to a clear brook and tells himself, “I must be clean, I must be clean.” Entering the water, he falls into “the quietest, sunniest, cosiest sleep that ever he had in his life” and wakes up reborn as a water baby, a little naked human form four inches long, “with a pretty lace collar of gills.” In this form Tom goes through a series of adventures involving a courtly salmon, a ferocious mother otter, and a dim-witted lobster. The story grows increasingly weird as its author’s great throbbing themes of purgative redemption and “muscular Christianity” crowd out any hope of narrative coherence.

The version of The Water Babies that was read to me as a child was much simplified, a heavily illustrated condensation of the story in rhyming quatrains, which appeared in a popular series of children’s literature called My Book House. I still have that volume, and when I open its mildewed pages to “Verses on Kingsley’s Water Babies,” I can recall the wondrous sense of possibility that held me spell-bound for so many childhood evenings. Perhaps my mother, who never learned to swim and who has had a lifelong terror of open water, invested her reading of this tale of an amphibious baby with a note of fear that seized my attention. And the story—with its naked water fairies, its obsessive note of fast-moving streams and sluicing tides, its protagonist’s tendency, upon misbehaving, to break out in highly suggestive “prickles”—had an unmistakable erotic timbre. It’s not surprising that over the years scholars have viewed The Water Babies as a parable of sexual awakening. Critics have described it as everything from a cautionary tale about masturbation to a wild fantasy of infantile regression in which the water itself is a symbol of the lost comforts of the womb. I was certainly not immune to the imagery of The Water Babies. The story disturbed me with its hints of death and altered states and with its insistence on some vague but powerful desire that I could as yet only dimly perceive. For whatever reason, it got hold of me. It seemed to me, at the age of three or four, that it really was possible to slip unobstructed from one dimension to another.

THE UNDERWATER WORLD WAS MAGICALLY accessible to me then, and I suppose I have never quite gotten over the disappointment that it did not remain so. When I was older, I liked to arrive at the neighborhood pool early in the morning, before any other swimmers had had a chance to rile the surface. Standing on the edge, savoring the chlorine fumes, I would follow with my eyes the black tile track of the lane markers as they descended the concrete slope that led to the deepwater drain. The water had a harsh, denatured brilliance, and I could see every dimple of peeling paint, every lost penny on the bottom with unnatural clarity, as if I was looking through a microscope. Curling my toe over the brick edgework of the pool, I would try hard to execute an elegant dive, wanting my body to pass with barely a whisper into the untouched water.

It seemed a cruel whim of nature that as soon as I entered this world, all the marvelous visual detail would disappear. My unprotected eye saw everything through a gauzy film, and the environment that a moment before had seemed limitless was now muffled and contracted. Even so, it was enough to be underwater, to be in another sort of place entirely. I would swim open-eyed along the pool bottom until my eyes were so stung and swollen by chlorine that I would lie in bed at night unable to sleep because of the pain.

The first face mask I owned was a dangerous toy bought at a drugstore. It was designed to fit not only over the eyes and nose but also over the mouth, creating an air chamber supplied by two long snorkels that protruded from the top of the mask and curved upward like the horns of a goat. At the ends of the snorkels were little cases in which floated Ping-Pong balls that were meant to stopper the breathing tube when the diver was submerged. I had never looked through a mask before and did not really understand its purpose. My hope was that it would allow me somehow to breathe underwater, but I was not prepared for the astonishing discovery I made the first time I put it on and slipped beneath the surface. It took only a few seconds for water to leak in through the imperfectly sealed fringes of the mask and flood the air space, but in that time I felt like a blind man whose vision had been restored. The human eye, as I had already discovered, is a faulty instrument when submerged. We see clearly on the surface because the fluid inside our corneas is dense enough to exert a pull on airborne light rays, bending them into focus on the retina. Underwater, the light rays are already traveling through a dense medium of their own, and the corneas’ power to direct them is much diminished.

When air is trapped in front of the eye, however, the situation is more or less corrected, and the images grow sharp again (though they often appear magnified by as much as one third). When I put on that mask I did not stop to ponder the physical law that brought everything into such supernal focus, I simply accepted these new conditions as a kind of gift. I put my wrinkled fingertips in front of the glass; they had the eerie clarity of a 3-D contour map. Once-blurry images were now sharp and immediate and somehow full of purpose. My eyes were so filled with vibrant detail that I felt like one of the saints we kept reading about in Catholic school—the unbeliever who finds himself suddenly trembling with ecstasy as he is “vouchsafed” a vision.

I don’t mean to say that that first descent into the pool wearing my leaky drugstore mask was a religious experience. But I was intrigued and unsettled in a way we can only be during those few childhood years when it is still possible to glimpse a new world without having guessed at its existence beforehand. It was a new world, and simply knowing that it was there, that I could enter it, filled me with a vague contentment. I had found the wormhole— the rent in the fabric of normal exist- ence—through which it was possible to enter some deeply satisfying other universe.

I thought of that knowledge as my secret, though of course millions of others were just as entranced, just as eager to pass through this mysterious portal. In the late fifties, “skin diving,” as it was then called, was only beginning to be perceived in the light of mainstream sanity. Until Jacques Cousteau and Emile Gagnan invented the demand regulator in 1943, recreational diving had been a cultish activity practiced mostly on the Mediterranean coast by men who referred to themselves as “gogglers” or “underwater hunters” and who banded together in associations that had wonderful names like Club Alpin Sous-Marin (Underwater Mountain-Climbers Club). Using only lung power, wearing motorcycle goggles, and carrying tridents and spears fashioned from umbrella ribs, they plunged into unexplored coral gardens that were still rich with primeval splendor, where the sluggish mérous and other prey fish had not yet been imprinted with the fear of man. The introduction of “scuba”—not yet a word but an acro- nym for self-contained underwater breathing apparatus—made diving a more intrusive sport. All at once the hu- man association with the underwater environment was no longer so exquisitely tentative.

SCUBA DIVING, FROM THE BEGINNING, had an air of dangerous allure. Every landlocked schoolboy knew of its intriguing hazards: The bends, which caused a diver’s veins to fizz with nitrogenated blood until he died a ghastly, percolating death; or rapture of the deep, which took away his reason, filled his heart with false contentment, and drew him down into the ocean gloom. Like millions of my contemporaries, I was transfixed by Sea Hunt, the TV series that featured Lloyd Bridges as a former Navy diver named Mike Nelson. In episode after episode, Mike Nelson would be found locked in deadly underwater combat with some evil agent or saboteur. Knives drawn, the two antagonists would cartwheel slowly through the water, each trying to sever his opponent’s air hose and send him gasping to the surface.

Nowadays scuba diving is a rather contemplative leisure-time activity, but back in the Sea Hunt days it was just another test of manly worth. I learned to dive when I was fourteen, in a YMCA pool in Corpus Christi, and like everyone else in the class, I imagined myself upon graduation patrolling the blue waters of the Gulf, a spear gun in my hand and an underwater Bowie knife in a plastic sheath strapped to my calf. The class itself, appropriately enough for these martial fantasies, was run like a boot camp. Our first task was to tread water for thirty minutes without using our hands, while the instructors made sarcastic comments from the side of the pool. The tanks we used were bare gray cylinders held onto our shoulders with canvas webbing that left deep impressions in the skin. The air in the tanks was delivered to our mouths by means of old-fashioned double-hosed regulators—the kind used by Mike Nelson himself—and their long accordion-pleated hoses fanned out from our faces like the gills of a salamander. In the classroom lectures, as terse as football skull sessions, we struggled to solve incomprehensible decompression problems and watched as the blackboard filled up with physical theorems and crude sketches of ruptured lungs.

I felt as if we were training to be not merely recreational divers but members of some elite underwater commando unit. I gloried in that illusion. My diving knife, for instance, was not just a mundane tool to free myself from fishing line and other underwater entanglements, it was the weapon with which I would one day rip open the hide of an attacking shark. But beyond all the warlike daydreaming and posturing was a deeper thrill. In the first few sessions, I had trouble getting to the bottom of the pool, since none of the techniques for equalizing pressure in my eustachian tubes seemed to work for me, and I was beset with a constant pain in my ears. Added to that was the simple problem of strangeness—the ungainly equipment, the dulled sensory awareness, the panicky sound of my own breathing as I drew and expelled the dry bottled air. Once I had passed through all these barriers, however, I detected in myself a kind of serenity. Hanging limply on the bottom with my fins barely grazing the concrete, looking out through the glass of my face mask, whose reversed letters assured me I was protected by a “tempered lens,” I felt a disembodied contentment—the contentment a soul is said to feel when it rises from the chrysalis of a cast-off body. At the age of fourteen, my body was practically new, but I was already a little weary of its predictable sensations and its burgeoning adult demands. Underwater, it had new properties; it had, for the first time, a grace of movement. With a portable air supply these sustained jaunts beneath the surface were a violation of the laws of nature, yet I felt more in conformance with the natural world than I ever had before.

Nowadays all scuba classes end with a check-out dive in open water, but in 1962 there was no such requirement. By the time I was through with my instruction, I had a joyless familiarity with the U.S. Navy decompression tables and a reasonable confidence that I could handle any diving emergency that might arise in a swimming pool. Answering an ad in the paper, I bought a used tank and regulator for $25. I took the equipment home and gazed at it wistfully, but something kept me from gathering it together and heading out into the Gulf with the fish hunters who had taught me to dive. Looking back, I realize I was simply afraid. The Gulf was vast and often rough, and the offshore oil platforms where all the diving was done were patrolled by hammerhead sharks and thousand-pound groupers that, according to legend, had actually gulped divers into their mouths. The Gulf of Mexico was not the point of entry I had imagined for myself—not the quiet little brook of The Water Babies but a roiling dark blue mass that could absorb an intruder like a vicious storm.

My secondhand equipment went unused and was passed on to another eager buyer when I went to college in Austin. In a landlocked university town during the late sixties, when almost every aspect of existence was caught up in urgent historical rumbling, my preoccupation with diving was merely a quaint relic. The reality around me was phantasmagorical enough. The ordered, limited world I had grown up with was suddenly capable of shape-shifting revelations. I remember the hysterical joy I experienced the first and only time I took LSD—joy because I felt confirmed in my belief that there was more, that human awareness did not necessarily need to end inside the cold gray walls that marked the boundaries of our conventional perceptions.

But strangeness has a short shelf life. Before long it turns into just another stale component of reality. As I passed through my twenties, as one daydream after another lost its conviction, I still craved the otherworldly sensations of diving.

FINALLY I WAS DRAWN BACK INTO IT. I had long since forgotten how to work the decompression tables and my certification card had expired, but I brushed up with a private instructor in the pool of an apartment complex and was soon reaccredited. I signed up for a three-day diving trip. The boat left from the coastal town of Freeport and ran all night to a deep, isolated reef—the northernmost coral reef in the western hemisphere—known as the Flower Gardens.

At dawn I looked out over the Gulf to see a big sea turtle surfacing twenty yards away. The turtle’s head was blunt, and its features conveyed an impression of morose curiosity. All around the creature was the infinite blankness of the ocean. It was eerie and exhilarating to imagine the sort of life that turtle led, as solitary as a comet wandering through space.

The sensation of jumping into the open sea that first time was as startling and absolute as I’d always imagined the sensation of skydiving would be. All at once, I was alone in the firmament, and though I was not hurtling downward, the feeling of suspension was just as intense.

It took me three or four calculated breaths to calm myself and look down past the blunt swaying tips of my fins. The water was a deep blue, and against this backdrop the expanding bubbles that arose from the diver below me were a brilliant silver, so sharply defined they looked like solid metal discs hurtling toward the surface. I grabbed hold of the descent line and lowered myself hand over hand. I had not gone five feet when my ears began to hurt. The trapped air in my eustachian tubes felt as dense as mercury, and there was no way I could relieve the pressure. I moved my jaws up and down, I pressed the mask against my face and exhaled, I swallowed and rocked my head from side to side, but the pain just grew more concentrated. I must have stayed there for ten minutes, humiliated, until finally, bit by bit, the pain lessened and I was able to sink slowly to the coral bank.

The divemaster took my hand as if I were a girl and led me around, pointing out the fan worms and Christmas tree worms that would pop back into their burrows as we approached them, the mustardy growths of stinging fire coral, a crevice from which a small spotted moray eel protruded, its flat body swaying in the current like a banner. The divemaster let go of my hand and gestured with a wide sweep of his arm at the seascape before me—the bulbous mounds of brain coral, the fissures and shallow canyons floored with blinding white sand. It was a theatrical, half-joking gesture, but I chose to read it seriously. Here is the place, the divemaster’s outstretched arm seemed to indicate, that you have been seeking.

I had only a glimpse on that dive, since I had depleted most of the air in my tank during my slow and stressful descent. I did not understand the radiant and unsettling forms of life that stretched out before me—the corals and fishes and anemones and the specks of plankton that swept over the reef like particles swirling in a beam of light. There was no way to focus on any one piece of the reef, to find some crucial illuminating detail that would help me perceive its purpose. The waving tentacles, the darting fish, the ceaseless secret business of the reef filled me less with wonder than with anxiety. My desire to comprehend this place was a kind of panic.

As I gained altitude, rising toward the surface and the shadow of the boat seventy feet overhead, the separate components of the Flower Gardens became a compacted, colorless mass. Barracuda hovered along the descent line, their teeth exposed in a carnivore’s rictus, their eyes ticking off my passage. Behind them was the ocean backdrop—it had the deep blue tincture of an approaching thunderhead. I wafted to the surface like a figure in a dream, and when I climbed back onto the boat, the memory of that first brief visit to the reef taunted me until it was time to go down again.

THAT WAS YEARS AGO. the dive is recorded in my first logbook, a pale blue vinyl notebook whose waterproof pages, bound with a plastic spiral, provide space for indicating visibility, bottom time, maximum depth, and temperature. I soberly entered this data, and on the lines reserved for “Comments,” I merely made a few guarded observations—“shallow coral heads; thermocline at 80′; barracuda; strong surface current.” There was no room to say more, and anyway I loved my terse declarative observations with their authoritative semicolons. At the time, those words seemed as well chosen and concentrated with meaning as the words of a haiku.

Eventually that first logbook was filled up, and then another. Brusque as they are, they seem to me now like dream journals, like diaries kept in a fever. Reading back through them fills me with nervous energy and with a kind of resentment that they do not constitute, as I had once hoped they would, the autobiography of an underwater pilgrim. The entries are too spotty for that, though the memories they evoke are vivid. On one page I am groping around blindly along the mud bottom of Matagorda Bay, searching with a group of Texas archaeologists for any nails or buckles or harquebus parts that might indicate the wreckage of the flagship of the Sieur de La Salle. Overhead, the engine of the research boat is running, its propwash deflected downward by means of an elbow-shaped aluminum housing that blasts away the oozy overburden, bathing us in turbulence and total darkness.

On another page I’m diving among giant clams off an island on the northwest coast of Madagascar. The island’s main village is called Hell-Ville. Its forests are populated with bug-eyed lemurs, its beach patrolled by a giant Aldabra tortoise named Caroline, who presents her neck, as thick as a python, to be stroked. Underwater, I pick up an empty cowrie shell from the sand bed and run my fingernail along its serrated aperture, producing a sound like that of a finger raking the teeth of a comb. Staring at the blurry brown spot on the back of the shell, I suddenly flinch, contracting the muscles at the back of my neck with the involuntary wisdom of a prey animal alert to its most vulnerable points of attack. The gleaming hide of a large shark passes from above into my field of vision, and I watch it sailing ominously over the reef—which, with its giant clams and undercut mushroom growths of coral, looks as defenseless as a hobbit village. The shark’s teeth are exposed in its lipless mouth, its nose is tapered to an artful wedge. The creature’s form is beautiful, but there is the terror of utter blankness in its eyes.

Or, I am diving off the coast of Southern California, at a place called Begg Rock, a barren islet that barely breaks the surface of the Pacific chop. I’m wearing a full wetsuit. The only place the water touches my skin is in the gap between the top of my mask and the rim of my neoprene hood, so that I feel as if I’m swimming with an ice cube on my forehead. Underwater, the rock is covered with scallops and anemones, their tendrils and tentacles—bright orange or red or yellow—vivid against the grim asteroid shading of the rock itself. Into view comes a face, a face so familiar and unthreatening that for an instant I almost raise my hand to wave. It is a sea lion, soaring toward me with languid winglike strokes of its front flippers. The sea lion comes within three feet of me, studies me frankly with its moist doglike eyes, and then veers way, its body spinning like a bullet. I watch it go, watch the dark blue water enfold it, and am left with an odd thought: a realization that the sea lion is now swimming through the Pacific with my image lodged somewhere in the circuitry of its brain.

THE LOGBOOKS FILLED UP, but the gaps between dives became longer and longer. I had three children; I had spiraling responsibilities of the sort that forced me to regard diving as an expensive recreational activity rather than as a life’s mission. I looked at those logbooks, at the paltry entries in the “total bottom time” column and felt almost shameful, as if the few underwater hours totaled there were, after all, the pitiful record of an abandoned spiritual quest. I read through the diving magazines—the ads for resorts and live-aboards in Aruba and Bonaire; the models posed in hot-pink wetsuits, lasciviously displaying some new gauge or contour-fitting buoyancy compensator—and grew self-righteous and edgy. I could not tolerate the notion that diving could be merely a hobby, but at the same time I envied the people in those magazine layouts—envied them their seemingly eternal leisure time, their perfect bodies, their gorgeous equipment, their casual, uncomplicated appreciation of a world that I had hungered for all my life but that continually eluded me, like some ungraspable goal in a homesick dream.

I sat on the edge of the bathtub as my youngest daughter discovered she could put her face underwater and open her eyes without coming to harm. Six inches of water, and nothing to see except the white curving shape of the tub—and yet night after night she plunged below the surface for as long as she could hold her breath, and I would watch her arms and legs thrashing as she tried to surge down into the depths she imagined were there. I knew what she wanted. She wanted to be at large in this sudden new territory, to pursue the illusion that she was fit to inhabit it, that its strangeness would embrace her.