The Hydra Club was a social organization of science fiction professionals and fans.
It was founded October 25, 1947 in the apartment of Judith Merril and Frederik Pohl on Grove Street in the Greenwich Village neighborhood of New York.
Among its members were Lester del Rey, David A. Kyle, Frederik Pohl, Judith Merril, Martin Greenberg, Robert W. Lowndes, Philip Klass, Jack Gillespie, David Reiner, L. Jerome Stanton, Fletcher and Inga Pratt, Willy Ley, George O. Smith, Basil Davenport,[1] Sam Merwin, Harry Harrison, Jerome Bixby, Groff Conklin, Bea Mahaffey, Murray Leinster, Jack Coggins, Avram Davidson[2] and J. Harry Dockweiler.
[3] An article by Merril about the club in the November 1951 Marvel Science Fiction was accompanied by Harry Harrison's drawing caricaturing 41 members: [4] Harrison's caption adds, "The remaining twenty-odd members showed up too late at the meeting."
On April 29, 1984, Judith Merril, by then living in Toronto, founded a similar group for the burgeoning science-fiction community there, which she dubbed Hydra North.