About G. C. Edmondson
G. C. Edmondson was the working name of science fiction author Garry Edmonson (full name "José Mario Garry Ordoñez Edmondson y Cotton") (October 11, 1922 in Washington state – December 14, 1995 in San Diego, California). According to the obituary published in Locus Magazine, Edmondson was born in Washington state During World War II he served as a U. S. Marine. Although generally called a science fiction writer, he wrote Westerns using the names Kelly P. Gast, J. B. Masterson, and Jack Logan. As he could also speak six languages he did translating work as well. His science fiction career began during 1955 with a story in the magazine Astounding. He later produced several novels which gained some note for their interest in time travel and Latin America. Several writers, including Gardner Dozois, tend to consider him as a neglected author.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.