WRITERS OFTEN THINK they know what's up.

Life is material, they'll say. Understanding human nature is part of the game.

And so there's a bit of schadenfreude built into the experience of reading Blood Will Out, Walter Kirn's account of being thoroughly and systematically duped, over a period of years and years, by a murderous con man.

In 1998—before publishing the novels Thumbsucker and Up in the Air—Kirn is living in Montana and working as a journalist. As a favor to his wife, he agrees to drive a crippled dog across the country, to Manhattan, where a wealthy dog-lover—a Rockefeller— waits to give it a good home. In the first of the many literary touchstones that stud the pages of Blood Will Out, Kirn picks up Travels with Charley to read along the way, expecting a quirky bit of Americana. Instead, he's surprised and depressed by John Steinbeck's gloomy, paranoid travelogue. Foreboding: established.

But Kirn gets the dog to New York, to the home of a man calling himself Clark Rockefeller; Kirn and Clark strike up an uneven friendship that persists for years—until just about the moment Clark is arrested for kidnapping his own daughter, revealed as a serial imposter, and eventually charged with murder.

The book jumps between flashbacks and the courtroom, as revelations are spun about Clark's many identities and the man he's accused of killing. Kirn is thoughtful on courtroom dynamics, self-critical about the character flaws that allowed him to fall into the con man's trap, and endlessly obsessed with Clark, comparing him frequently to the shape-shifting Ripley of Patricia Highsmith's novels. The resulting book is less lascivious by half than most true-crime stories, and twice as smart.