New York, Harcourt, Brace & World, 1966. First edition, first impression. Hardback. A very good copy of a superlative example of science fiction. An important piece. First published in a shorter form in 1959 in the Magazine of Fantasy and Science Fiction. A nice copy, spine a little toned and spotted, a couple of short tears to the jacket edges, with a ragged one across the author's name at the top of the spine. Top edge a little foxed. Seller's sticker to rear of jacket. A nice copy overall. Cover art by Carl Smith [9253, Hyraxia Books].