Spine/covers show some shelf wear/scuffing. Spine has a crack, but everything is still firmly attached to covers. Foxing
One of Norton's Ross Murdock time travel novels (The Time Traders, etc.). Ace F-287. "Time Agents Ross Murdock and Gordon Ashe, aided by a Polynesian girl and her team of telepathic dolphins, probe the mystery of the sea-planet men have named Hawaika. Its cities and civilizations have vanished, but our agents are snatched back through a Time Gate and marooned in the midst of the struggle for power that must have destroyed the planet.
"The richness which Andre Norton lavishes on her portraits of the wonder-worlds of the universe, the subtle warmth of the empathic relations she portrays between men and mutated animals, and above all the mysteries she suggests and half-reveals -- these, in the words of another book, are stories, O my brothers!" P. Schuyler Miller (Analog); 16mo - over 5¾" - 6¾" tall