Off-duty infantrymen of Lima Company, 3rd Battalion, 7th Marines reading GATES OF FIRE, Al Anbar Province, Iraq. Photo by Company Commander Capt. Dominique Neal, courtesy Capt. David Danelo.

BOOKS AND BATTLES A former Marine Captain in Afghanistan and Iraq tells of the books that helped him most.

During my earliest training as a Marine Corps infantry officer, in 1998, the tactics instructors would point to the piles of manuals on our desks and say, "Memorize them -- they're written in the blood of Marines who went before you." Even in that relatively peaceful year, we sensed that combat lessons were best absorbed vicariously -- better to learn from others' experience than from your own mistakes. Four books helped guide me along the path of becoming a warrior, fighting in Afghanistan and Iraq, and returning home afterward.

I read Steven Pressfield's Gates of Fire in an airport lounge on a Sunday afternoon in 2000, two years after it was first published. I was a newly commissioned second lieutenant returning to Camp Pendleton, Calif. after spending Christmas with my family in Baltimore. Pressfield drew me into his fictional tale of the Spartans' warrior spirit at Thermopylae. Three hundred Spartan infantrymen held off the invading Persians long enough to save Greece and perhaps all of Western civilization.

A military leader's duty to his subordinates, Pressfield writes, is "to fire their valor when it flags and rein in their fury when it threatens to take them out of hand." He is "just a man doing a job. A job whose primary attribute is self-restraint and self-composure, not for his own sake, but for those he leads by his example. A job ... of 'performing the commonplace under uncommonplace conditions.'" If there's a better description of combat leadership, I've not seen it. I recognized Pressfield's characters in the men I was serving with; weapons and tactics evolve, but the people stay the same. After returning to Pendleton, I gave the 43 Marines in my platoon one week to read Gates of Fire. A few months later, after the publication of Pressfield's next novel, Tides of War, I found nearly every Marine in the platoon reading it on his own.