This ACE Double from 1967 features two sci-fi classics - "The Rival Rigelians" by Mack Reynolds and "Nebula Alert" by A. Bertram Chandler. The first story follows the interstellar conflict between the humanoid inhabitants of Earth and the insectoid Rigelians, while the second tale features the crew of the space vessel Rimfire as they discover a dangerous alien entity. Both novels are in their original paperback format and have been well-preserved over the years. Whether you're a collector of vintage sci-fi or simply a fan of classic tales, this ACE Double is a must-have addition to any library.