The Green Valley News reports that Boyer died Thursday in Tucson.
His trilogy consisted of "The Suppressed Murder of Wyatt Earp," ''Wyatt Earp's Tombstone Vendetta" and "I Married Wyatt Earp."
Ben Traywick, historian emeritus of Tombstone, says Boyer was a giant in the field of Earp history.
Boyer served in the U.S. Army Air Corps in 1943 and retired from the Air Force in 1965 as a lieutenant colonel.
The Wisconsin native began his Earp research after leaving the military.
Boyer also published other books, including several works of fiction.
He is survived by his wife, Jane Candia Coleman, a son and a stepson.