Books about Human-alien encounters -- Fiction (sorted alphabetically)
- Routine for a Hornet Don Berry
- Rx Alan Edward Nourse
- Satellite of Death Randall Garrett
- Satisfaction Guaranteed Joy Leache
- Savage Galahad Bryce Walton
- Scandalized Martians Arnold Marmor
- Scapegoat Richard Maples
- Secret of the Martians Paul W. Fairman
- Sentimentalists Murray Leinster
- Serpent River Don Wilcox
- Shadrach" Nelson S. Bond
- Shock Troop Richard Bolton
- Short Snorter Charles Einstein
- Sidewinders From Sirius Fox B. Holden
- Sinister Invasion Edmond Hamilton
- Slaughter on Dornell IV Randall Garrett and Robert Silverberg
- small bears Gene L. Henderson
- Snowbank Orbit Fritz Leiber
- Space brat Henry Slesar
- Spacemen lost George O. Smith
- space visitors Edmond Hamilton
- Spawning Ground Lester Del Rey
- Special Delivery Kris Neville
- Specimen Charles V. De Vet
- Spoilers of the Spaceways W. Bradford Martin