"At a certain time in your life, you think about death in a serious way, and you think about it often," muses Dave Robicheaux in James Lee Burke's latest novel, "Swan Peak" (Simon & Schuster, 416 pages, $26).

One might assume Robicheaux, who has found himself in harm's way in 16 previous books, thinks about death quite a bit. Even his vacations come with a high body count.

"Swan Peak" arrives on the heels of what may be Burke's best novel, the post-Katrina elegy "Tin Roof Blowdown," and while it doesn't quite measure up to that book's haunting resonance, it's still a hell of a ride. There are more lowlifes and psychopaths per square inch in "Swan Peak" than in three or four books by other suspense writers, and the point of view changes so quickly it can leave you shaking your head. But overall, Burke provides another meaty, thoughtful exploration of why men do the evil that they do.

Robicheaux, on leave from his job as a New Iberia detective, and his wife, Molly, have unwisely chosen to vacation in Montana with his old partner Clete Purcel. The violence-prone P.I. manages to land them in conflict with a wealthy oilman and his brother by fishing in the wrong stream. The Wellstones got rich in Texas and now seem to be entangled with a fundamentalist Christian movement that includes a predatory preacher, but there are far more disturbing elements afoot.

Two college students are viciously murdered above Robicheaux's lodgings. Ugly conflicts arise with the Wellstones' hired hands. An itinerant bluesman with a mysterious past wanders into town, a vengeful Texas prison guard, formerly of Abu Ghraib, on his trail.

Even more disturbing, though, may be the repeated insinuations that a ghost from Clete's past has returned.

A relentless passion for revenge runs strongly through "Swan Peak," as does Burke's pensive acknowledgment of man's propensity for violent and selfish acts. Robicheaux, who has cheated death many times, has learned some lessons over the years, none of them pretty. "The great joke," he says, "is that any wisdom most of us acquire can seldom be passed on to others." Fortunately, Burke's understanding of the fragility of men's souls again proves lucid and compelling.