To borrow a phrase from Robert A. Heinlein, I try not focus too narrowly on any given topic; it's the surprises that are most interesting...
For those of you who do not have access to my LinkedIn "Reading List by Amazon," here are some of my non-fiction shooting, hunting, fighting, and warfare favorites:
1776 by David McCullough
Band of Brothers: E Company, 506th Regiment, 101st Airborne from Normandy to Hitler's Eagle's Nest by Stephen E. Ambrose
A History of Warfare by John Keegan
A Hunter's Wanderings in Africa: Being a Narrative of Nine Years Spent Amongst the Game of the Far Interior of South Africa by Frederick Courteney Selous
African Rifles & Cartridges by John Taylor
After Big Game in Central Africa by Edouard Foa
Archaeological Perspectives on the Battle of the Little Bighorn by Douglas D. Scott, Richard A. Fox Jr., Melissa A. Connor, Dick Harmon
Archaeology, History, and Custer's Last Battle: The Little Big Horn Re-examined by Richard Allan Fox Jr.
Beyond Fair Chase: The Ethic and Tradition of Hunting by Jim Posewitz
Big Game Hunting and Collecting In East Africa, 1903-1926 Kalman Kittenberger
Citizen Soldiers: The U. S. Army from the Normandy Beaches to the Bulge to the Surrender of Germany by Stephen E. Ambrose
Cooper on handguns by Jeff Cooper
1754-1766 by Fred Anderson
Days Afield: Journeys and Discoveries in Hunting and Fishing by Thomas McIntyre
Death in the Desert: The Fifty Year's War for the Great Southwest by Paul I. Wellman
Dispatches by Michael Herr
Fireworks: A Gunsite Anthology by Jeff Cooper
Ghost Soldiers: The Epic Account of World War II's Greatest Rescue Mission by Hampton Sides
Herodotus: The Histories by Herodotus *
Hiroshima by John Hersey
Hit Or Myth by Louis Awerbuck
Homage to Catalonia by George Orwell
Horned Death by John Burger
In the Gravest Extreme: The Role of the Firearm in Personal Protection by Massad F. Ayoob
Instinctive Shooting by G. Fred Asbell
Kill or Be Killed: The Rambling Reminiscences of an Amateur Hunter by Major W. Robert Foran
Kursk: The Clash of Armour by Geoffrey Jukes
Lion-Hunting in Somali-Land by C. J. Meliss
Longbow: A Social and Military History by Robert Hardy
Moving Mountains, Lessons in Leadership & Logistics From the Gulf War by Lt. Gen. William G, Pagonis
No Second Place Winner by Bill Jordan
Of Arms and Men: A History of War, Weapons, and Aggression by Robert L. O'Connell
On Killing: The Psychological Cost of Learning to Kill in War and Society by Dave Grossman
One Bullet Away: The Making of a Marine Officer by Nathaniel C. Fick
Principles of Personal Defense by Jeff Cooper
Quartered Safe Out Here: A Harrowing Tale of World War II by George MacDonald Fraser
Rifles For Africa by Gregor Woods
Roman Warfare by Adrian Goldsworthy
Safari Rifles by Craig Boddington
Sharpshooting For Sport And War by William Wellington Greener
Shots at Big Game by Craig Boddington
Shots fired in anger: A rifleman's view of the war in the Pacific by John B George
Son of the Morning Star: Custer and The Little Bighorn by Evan S. Connell
Stalking & Still-Hunting by G. Fred Asbell
Street Smart Gun Book by John Farnam
That Every Man Be Armed by Stephen P. Halbrook
The AK47 Story by Edward Clinton Ezell
The Art of the Rifle by Jeff Cooper
The Art of War in the Middle Ages: A.D. 378-1515 by Charles Oman
The Combat Shotgun And Submachine Gun: A Special Weapons Analysis by Chuck Taylor
The Complete Book Of Combat Handgunning by Chuck Taylor
The Face of Battle by John Keegan
The Farnam Method of Defensive Handgunning, Second Edition by John S. Farnam
The Fighting Rifle: A Complete Study of the Rifle in Combat by Chuck Taylor
The Hunting Rifle: Design, Selection, Ballistics, Marksmanship by Townsend Whelen
The Mask of Command by John Keegan
The Modern Technique of the Pistol by Gregory B. Morrison
The Lost Art of War: Recently Discovered Companion to the Bestselling The Art of War by Sun-Tzu
The Rifle in America by Philip B. Sharpe
To Ride, Shoot Straight & Speak the Truth by Jeff Cooper
The Wild Blue: The Men and Boys Who Flew the B-24s Over Germany 1944-45 by Stephen E. Ambrose
Up North (Outdoor Essays & Reflections) by Sam Cook
Use Enough Gun by Robert Ruark
With British Snipers to the Reich by Capt. C. Shore
* Okay, Herodotus was pretty fanciful, less so than Homer - who was clearly a storyteller without pretense, but not nearly so careful as Thucydides - the West's first serious historian.
UPDATE: As of late March 2012 I have discovered Goodreads and have moved many of my reading details here http://www.goodreads.com/michael_brady