Gregory Mast enlisted in the Marine Corps in 1978 and was commissioned in 1983. Following his active military service he worked in the defense industry on classified projects, as a web communications specialist at design studios, as a freelance graphic designer, and has owned a traditional Irish pub. He and his wife live in San Jose, California.
Hans Halberstadt studied documentary film in college and later took up writing, authoring or co-authoring more than fifty books. Most of his books have been on military subjects, especially U.S. special operations forces, armor, and artillery. He has also written extensively about farming and railroads. Halberstadt served in the U.S. Army as a helicopter door gunner in Vietnam. He and his wife, April, live in San Jose, California.