
In honor of Veterans Day, I thought it would be appropriate to feature crime fiction books either written by veterans or featuring a veteran as a protagonist. You don't have to look very far down current and former best-seller lists to uncover the latter, beginning with Walter Moseley's popular series set in the 1940s featuring Ezekiel "Easy" Rawlins, a black World War II veteran. The first installment was Devil in a Blue Dress (later made into a motion picture with Denzel Washington), and the most recent—and possibly the last—in the series, is this year's Blond Faith.
Travis McGee, a creation of mystery writer John D. MacDonald, appeared in 21 novels, from The Deep Blue Good-by in 1964 to The Lonely Silver Rain in 1984. Although a a self-described "beach bum," he was also a Korean War veteran. MacDonald himself was also a veteran serving first in the army Ordnance Corp, then the OSS in the Far East during World War II. While still in the military, his literary career began accidentally when he wrote a short story in 1945 and mailed it home for the amusement of his wife. She submitted it to the magazine Story without his knowledge, and it was accepted. In the first four months after his discharge, he allegedly concentrated solely on writing short stories, generating some 800,000 words and losing 20 pounds while typing during 14-hour daily sessions seven days a week.
Relative newcomer Chris Grabenstein features protagonist John Ceepak, a former military policeman in Iraq with a strict moral code and some leftover demons from the war, in a humor-tinged series with such titles as Tilt-a-Whirl, Mad Mouse, and Whack a Mole, although the subject material is often serious.
There are many other mysteries with veteran protagonists, but I'll post a few below grouped by war experience. Since November 11th is Veteran's Day in the U.S. I focused primarily on protagonists who are U.S. military veterans, the exception being Maisie Dobbs by Jacqueline Winspear and Lord Peter Wimsey by Dorothy Sayers, since there are a dearth of American WWI veteran-related mysteries (and Sayers is of course a crime fiction legend).
American Civil War
Owen Parry, Faded Coat of Blue
Brent Monahan, a series with sheriff/veteran John Le Brun
Mexican-American War
Michael White, Soul Catcher
World War I
Baynard H. Kendrick, a series featuring blinded veteran Captain Duncan Maclain
Dorothy L. Sayers, series with Lord Peter Wimsey
Jacqueline Winspear, a series featuring nurse veteran Maisie Dobbs
World War II
Terence Faherty, a series featuring veteran Scott Elliott
William Hjortsberg, Fallen Angel
Robert B. Parker, Double Play (featuring veteran Joseph Burke, not Parker's usual Spencer)
Korean War
James Lee Burke, The Lost Get-Back Boogie
Stephen E. Miller (author and actor), The Woman in the Yard
Kris Nelscott, series featuring African-American detective/veteran
Vietnam War
Richard Barre, series with Wil Hardesty
Austin Bay, The Coyote Cried Twice
George C. Chesbro, Veil and Jungle of Steel and Stone
James Crumley, The Mexican Tree Duck
Nelson DeMille, Up Country
Jerome Doolittle, several novels featuring protag veteran Tom Bethany
MIchael Allen Dymmoch, series with former medic John Thinnes
Joseph Flynn, Digger
Katherine Forest, series with former marine, Kate Delafield
Ken Grissom, Drop-Off
Gar Anthony Haywood, series with veteran Aaron Gunner
Jeremiah Healy, series with John Francis Cuddy
Craig Johnson, series feauturing Walt Longmire, veteran Marine Investigator
Rick Riordan, Cold Springs
Conall Ryan, Black Gravity
Howard Swindle, Jitter Joint
Sharon Wildwood, Some Welcome Home (one of the few featuring a nurse veteran)
Gulf War (Desert Storm)
Charles Benoit, Noble Lies
J.D. Rhoades, series with Jack Keller
Jim Tenuto, Blood Atonement: A Dahlgren Wallace Mystery
Other Veterans (non-war-specific)
Lee Child, series with Jack Reacher, former military police
Julia Spencer-Fleming, series with former helicopter pilot, Claire Fergusson
Wendi Lee, series with former marine Angela Matelli

In addition to John D. MacDonald above, military veterans who have penned crime fiction include James Church (a pseudonym), a former Western intelligence officer with decades of experience in Asia. In A Corpse in the Koryo, Church introduced readers to elusive Inspector O. The mystery was named one of the best mystery/thrillers of 2006 by the Chicago Tribune.
Steve Coonts received his Navy wings in August, 1969. After completion of training in the A-6 Intruder aircraft, Coonts reported to Attack Squadron 196 at NAS Whidbey Island, Washington. He made two combat cruises aboard USS Enterprise during the final years of the Vietnam War as a member of this squadron. After the war he served as an instructor on A-6 aircraft for two years, then did a tour as an ssistant catapult and arresting gear officer aboard USS Nimitz, finally leaving active duty in 1977. His first novel, Flight of the Intruder, published in 1986 by the Naval Institute Press, spent 28 weeks on the New York Times bestseller lists in hardcover. A motion picture based on this novel, with the same title, was released in 1991.
Chet Cunningham was drafted into the army in 1950. After nine months in Japan, he moved to the front lines of the war in Korea, participating in two battles and numerous line-crossing and prisoner patrols. Assigned to a heavy weapons company he served as an 81 mm mortar gunner, squad leader, and section leader. His service earned him the Combat Infantryman's Badge. After two years of service he was discharged in the rank of sergeant. Cunningham has written many mysteries and thrillers, under the pen names of Keith Douglass and Don Pendleton.
Samuel Dashiell Hammett joined the army during the first world war, serving in the Motor Ambulance Corps, unfortunately contracting TB in the process. He earned a disability pension from the Veterans Bureau on his discharge, and when his health permitted tried to resume his former work with the Pinkerton’s Detective Agency. Sponsored by the Veterans Bureau, he signed up for a writing course and in a short space of time began a campaign of magazine submissions. Hammett went on to write several short stories and five novels, the most famous among them The Maltese Falcon.
Wayne Karlin's Lost Armies features a Vietnam vet teaching English to Vietnamese refugees in southern Maryland and a "tripwire" vet who is terrorizing them. Karlin served in the U.S. Marine Corps from 1963 to 1967, when he was honorably discharged with the rank of sergeant. His decorations include the Vietnam Service Medal, the Air Medal, a Presidential Unit Citation, and the Combat Air Crew Badge with three stars. Karlin is a professor of Languages and Literature at the College of Southern Maryland, and has also authored or editor other books and anthologies on the war, as well as essays.
Robert B. Parker, author of the popular Spencer series, served with the Army in Korea. His protagonist, the Boston P.I. Spencer, is also a Korean War veteran, and was first seen in 1973's The Godwulf Manuscript, with dozens more novels following. The character of Spencer was made into a TV series Spenser: For Hire during the 1980s.