Contents: • Biographical Comments • The Callistan Menace • Ring Around the Sun • The Magnificent Possession • Trends • The Weapon Too Dreadful to Use • Black Friar of the Flame • Half-Breed • The Secret Sense • Homo Sol • Half-Breeds on Venus • The Imaginary • Heredity • History • Christmas on Ganymede • The Little Man on the Subway by Isaac Asimov and Frederik Pohl • The Hazing • Super-Neutron • Not Final! • Legal Ritesby Isaac Asimov and Frederik Pohl • Time Pussy • Author! Author! • Death Sentence • Blind Alley • No Connection • The Endochronic Properties of Resublimated Thiotimoline • The Red Queen's Race • Mother Earth