Books about Human-alien encounters -- Fiction (sorted alphabetically)
- Cosmic Bluff Mack Reynolds
- cosmic jackpot George O. Smith
- Cosmic Saboteur Frank M. Robinson
- Cosmic striptease Harlan Ellison
- Cosmic Tragedy Thomas S. Gardiner
- Course of Logic Lester Del Rey
- Crisis! C. M. Kornbluth
- Crisis on Titan James R. Adams
- Crowded Colony Jerome Bixby
- Cry from a Far Planet Tom Godwin
- Crystal Circe Henry Kuttner
- Cultural Exchange Jesse F. Bone
- Customs Lounge Annie Proulx
- Dancers Margaret St. Clair
- Dark Goddess Richard S. Shaver
- Daughter Philip José Farmer
- Dawningsburgh Wallace West
- Day of Wrath Bjarne Kirchhoff
- Definition Damon Knight
- Destination—Death Wilbur S. Peacock
- Devil of East Lupton, Vermont Murray Leinster
- Diplomatic Immunity Robert Sheckley
- Don't Panic! Robert W. Krepps
- Doorstep Keith Laumer
- Double Spy Dan T. Moore