During what war was the novel "The Short-Timers" set?

"The Short-Timers" is a 1979 semi-autobiographical novel by U.S. Marine Corps veteran Gustav Hasford, about his experience in the Vietnam War. It was later adapted into the film "Full Metal Jacket" (1987) by Hasford, Michael Herr, and Stanley Kubrick. Hasford's novel "The Phantom Blooper" (1990) is a sequel to "The Short-Timers". The book was supposed to be the first of a trilogy, but Hasford died soon after completing its sequel and before writing the third installment.

The book is divided into three sections, written in completely different styles of prose, and follows James T. "Joker" Davis through his enlistment in the United States Marine Corps and deployment to Vietnam. "The Spirit of the Bayonet" chronicles Joker's days in recruit training, where a drill instructor (Gunnery Sergeant Gerheim) breaks the men's spirits and then rebuilds them as brutal killers. "Body Count" shows some of Joker's life as a war correspondent for the Marines in 1968. "Grunts" takes place on a mission through the jungle outside of Khe Sanh.

According to the Gustav Hasford web-site maintained by Hasford's cousin, Jason Aaron, "The Short-Timers", "The Phantom Blooper", and Hasford's third and last completed book, a noir detective novel titled "A Gypsy Good Time" (1992), are currently out of print. The texts of the two war novels and an excerpt of A Gypsy Good Time were publicly available at the web-site for at least a decade,  but the site has since been redesigned.