- J2
- Jack and the Aktuals, or, Physical Applications of Transfinite Set Theory
- Jack of Eagles
- Jackpack City
- James Blish SF Gateway Omnibus
- Janus Arrival: Journey's End
- Janus Challenge: The Journey
- Japan Sinks
- Jemma 7729
- Jenna Starborn
- Jenseits aller Galaxien: Science Fiction Sammelband
- Jenseits der Zeit
- Jericho Calling
- Jerry Quarry Died for Our Sins
- Jeu de Rang
- Jinian Footseer
- Jinian Star-Eye
- Jinian Star-Eye
- Jintao
- Job Hunter
- John Carter - Der Riese und die Gelben vom Mars
- John Sladek SF Gateway Omnibus
- Joker Moon
- Journals of the Plague Years
- Journey Time
- Journey To Mars, A Space Odyssey
- Journey to the Andromeda Galaxy
- Journey to the Center of the Earth
- Journey to the Centre of the Earth
- Journey's End : An Asian Alternate-History Science Fiction Saga
- Journeys to the Planet Mars, or, Our Mission to Ento
- Jouth # 3
- Jouth #1