Science Fiction Forum was a critical journal of science fiction. It was created by Damon Knight and James Blish in 1957. Lester del Rey was also an editor.
A famous essay by Damon Knight on the symbolism in James Blish's short story "Common Time" was published in a 1957 issue, and later reprinted in Knight's In Search of Wonder.
The magazine led to the creation of the Science Fiction Writers of America.