NONFICTION: "The Long Walk," by Brian Castner.

On a sunny afternoon in the calm civic space of the Pearl District in Portland, Ore., a perfectly normal technical consultant steps off the curb to cross the street. As soon as his foot hits the asphalt, though, he's gone Crazy. In a sense it is no wonder, since for the past five years, he's been expecting a bomb to go off.

As the commander of an Explosive Ordnance Disposal Unit, Brian Castner did three tours in Iraq. His job was not always terrifying, and people didn't "dissolve into red mist" in front of him, but his days on duty were certain to contain three things: too much Red Bull, too many body parts and the howling of public grief.

The Crazy, as Castner calls it in his memoir, "The Long Walk," is as much a neurological as a psychological condition. Cleaning up after suicide bombings, with the constant expectation that things could, all of a sudden, become deadly, along with the constant evidence of the body's fragility, would put anyone in a fight-or-flight state. That Castner and his crew work efficiently and expertly under these conditions is a testament to the implacable beauty of good training. The Air Force is one of the last places where things are not supposed to be easy; on the other end of his grueling course, however, Castner emerges with a sense of accomplishment and belonging:

"EOD school builds in complexity and momentum every day. ... Explosive theory becomes practical application. ... Applying what you learned in demolitions in Month 1 to dissect a Soviet guided missile five months later. ... I entered EOD school a skinny dumb kid. ... I left a focused, dedicated, obsessive, invincible man whose only purpose was to go to Iraq and blow things up."

It seems strange, given all the attention to detail, that Castner's training didn't include some way to prepare for the inevitable emotional fallout of his daily life in the Air Force. If they can give you a good grasp of physics and the fundamentals of ordnance, it seems they should be able to tell you how your brain will react to the aftermath of a suicide bombing in a hospital for crippled children, to the sound of women's constant wailing, to the evidence, everywhere, of hate and mortality.

Instead, Castner is left with "the Crazy." Outwardly a suburban husband, father and teacher, he spends most of his time running, "left eye twitching, Crazy in my chest and mind." At first, Castner believes that he is dying from a heart attack. When tests reveal nothing wrong, he shamefully contemplates PTSD, a condition he feels he has no right to, since he hasn't seen his best friends killed in front of him. By the time a therapist points out that he does not have PTSD, but that his is a healthy human mind reacting the only way a healthy human mind could react, the reader is nearly as wrung out as Castner himself.

There are many memoirs of trauma-affected minds, and there are sure to be more coming as vets keep returning. Castner's is an opening salvo in a defensive war. With the level of traumatic brain injuries on the rise, with suicide bombings and IEDs the new enemy, war has gone from simply ravaging the physical landscape to mutilating the bedrock neurology of our warriors. Castner's book maps out this new and sorrowful territory with the skill and focus of someone who has had to defuse a bomb inside his own body.

Emily Carter lives in Connecticut and is the author of "Glory Goes and Gets Some."