William "Bill" Daniel Ehrhart is an American poet, writer, scholar, and Vietnam veteran. Ehrhart has been called "the dean of Vietnam war poetry" and is the author of more than 30 books, including Vietnam Perkasie: A Combat Marine Memoir, Passing Time: Memoir of a Vietnam Veteran Against the War, Busted: A Vietnam Veteran in Nixon's America, and Thank You for Your Service: Collected Poems.