A brilliant narrative by Outside magazine editor Hampton Sides pivots 180 degrees from lamentation. He has readers peer, as James Earl Ray did, through the crosshairs of the Remington Gamemaster aimed at the Rev. Martin Luther King Jr.: "The soft-nosed slug ... sliced through his shirt collar and coat lapel and cleanly sheared away the taut cinch of his brown necktie ... "

The Rev. King had, by 1968, coalesced a broad black and white moral coalition, facing down the South's seething, still-normal racial hatred. And segregationist George Wallace was running for president. That would, King said, " ... arouse many evil forces."

Ray, who had fled prison in 1967 crouched in a bread crate, had drifted into Mexico and back through the South, smoking dope, robbing stores, even collecting a few signatures for Wallace's campaign. Ray pasted the supremacist slur "Martin Luther Coon" on his TV set. He was obsessed.

Hampton Sides details the passion of King's demise. It's horrible and mundane. Ray, a health crank, scarfed supplements and wheat germ and frequented hypnotists to gain the secrets of power over others. He carried around a self-help book, "How to Cash in on Your Hidden Memory Power." He had a furtive manner, and took cha-cha lessons to meet Latin women. But, he wrote, "You can't trust anyone too far, especially the women type." He had "rabbit little tics: the way he constantly tugged on his left ear, the weak nervous giggle."

On assassination morning, Ray "ate breakfast, most likely at the New Rebel restaurant, and then checked out, taking several small bars of Cashmere soap. ... He bought a copy of the Memphis Commercial Appeal [which] featured a page-one photograph of King standing in front of Room 306 at the Lorraine" -- the motel where, before sunset, Ray would shoot him.

Ray embodies malicious purpose -- a quirky, furtive hater as trivial, heedless and lucky as he was history-altering. "Hellhound on His Trail: The Stalking of Martin Luther King Jr. and the International Hunt for His Assassin" flickers between converging scenes of Ray, King and Wallace -- and of Memphis itself amid the biracial garbage workers' strike that drew King. Sides proceeds toward catastrophe with the awed stateliness of a Greek tragedy.

In the aftermath, the book briefly stills; a reader might guiltily skim the elegies for King, skipping ahead to the international detective work and long, gripping chase. Ray managed to visit his brother (who perhaps funded Ray), enter Canada, con a passport in a policeman's name, fly to London, armed, wander to Portugal and back. Finally caught in London after two months and jailed in Tennessee, he again escaped for a few days, perhaps with the help of admirers.

Sides sets Ray's banal racial loathing against King's brave public confrontations of hatred. He leaves the rest to readers.

Mark Kramer was founding director of the Nieman Program on Narrative Journalism and writer-in-residence at Boston University and Smith College. He lives in Massachusetts.