Elizabeth D. Samet is the author of “Soldier’s Heart: Reading Literature Through Peace and War at West Point.”

...In fact, the average life expectancy of an officer in a British bomb disposal unit at the time [London, 1940] was 10 weeks. Spectacular failure was a common outcome of a technician’s encounter with a bomb. Yet the Royal Engineers remained undaunted. This was “the Heroic Age of bomb disposal,” declares Maj. A. B. Hartley, the historian of the bomb units and one of the service’s veterans, “a period of individual prowess when urgency and a lack of knowledge and equipment led to the taking of fantastic risks, to fantastic escapes, and to many, many deaths.”...

This period was also, explains Brian Castner in “The Long Walk: A Story of War and the Life That Follows,” the first of two instances in “modern war” during which “the bomb technician found himself a historic fulcrum.” The second was the Iraq war — Castner’s war. A former Air Force officer, Castner commanded an Explosive Ordnance Disposal (E.O.D.) unit in Iraq. Later, as a civilian contractor, he conducted predeployment training in tactical bomb disposal for the military.

“Our first chance we won,” he says of the British response to German bombing, the “we” signaling a solidarity among specialists that transcends time and place. The resourcefulness of the British bomb technicians during the blitz, Castner argues, “ultimately shifted the strategic direction of the war.” By contrast, he insists, the second opportunity was entirely missed — “we failed before we started” — when coalition forces on their way to Baghdad in 2003 did not destroy the country’s many unguarded ordnance depots. Instead, they allowed ammunition bunkers to be “stripped clean by Iraqi militants and redistributed” for Castner and his E.O.D. brothers and sisters to subsequently “dispose of one by one, hidden by the side of the road.”...