New York, Doubleday, 1957. First edition, first impression. Hardback. A very good copy. In Pringle's 100 Best SF Novels, along with Wyndham's Midwich Cuckoo's [Pringle, p57]. Jacket a little faded to the spine, with some light wear to the corners. Price sticker to the rear. Nicer than usually found. Cover art by Mel Hunter [9504, Hyraxia Books].