Horizons was edited by Harry Warner, Jr. for more than 60 years.
Horizons was a science fiction zine published in Hagerstown, Maryland, U.S.A. The first issue appeared in October, 1939, and the zine was published until Harry Warner, Jr.'s death in 2003. Approximately 250 issues of the quarterly publication were produced. It is believed to be the longest continually published fanzine in history. It was usually distributed through the Fantasy Amateur Press Association.