Brian Aldiss, the most prominent British editor of anthologies, began with three small paperback volumes for Penguin Books, Penguin Science Fiction (1961), More Penguin Science Fiction (1963), and Yet More Penguin Science Fiction (1964), that were subsequently gathered into this Omnibus in 1973, the same year that Aldiss published in influential Billion Year Spree: The True History of Science Fiction.
The cover shown here is of a 1986 reissue edition.