"Years ago, in state documents, Vachel Carmouche was always referred to as the electrician, never as the executioner." This stately but ominous opening line kick-starts Purple Cane Road (Doubleday), the crown jewel of James Lee Burke's Dave Robicheaux series. The Houston native wrings enough nuance, danger, and humor out of a single page to stock your garden-variety mystery writer's dialogue larder for months. The emotionally taut story line revolves around Robicheaux's investigation into his mother's long-ago murder at the hands of the police. This is the finest hard-nosed detective writing so far this year and may stand as one of the best of the decade to come.