He was born in San Francisco and attended Grattan School and Lowell High, achieving the highest honors.
Inman graduated from Stanford with distinction (Phi Beta Kappa) in 1952, and was awarded back-to-back Fulbright Scholarships in German Literature in Graz, Austria.
In 1960, Inman and his family moved to Colorado, where he began his first novel and worked as an editor, reporter and librarian for the Denver Post.
He later lived in San Francisco and New York City, where he was the editor of all six scientific journals for the American Institute of Aeronautics and Astronautics, from 1983 to 1987.
Inman published other numerous short stories and articles, and was awaiting publication of a new novel, Delphi, when he died suddenly at the age of 75.