Spine reinforced with 2" non-yellowing library tape

This edition restores the title of the magazine serial (from Astounding 1955-56.) The first hardcover was titled The Dragon in the Sea, and this title was used on most editions through 1971 / (first paperback was titled 21st Century Sub.) I am particularly fond of John Berkey's fabulous wraparound cover - I think it one of his best.