Encyclopedias, Almanacs, Transcripts, and Maps
- Claude Adrien Helvetius
- Claude Chappe
- Claude Chevalley
- Claude de Jouffroy d'Abbans
- Claude Garamond
- Claude-Louis Berthollet
- Claudius Amyand
- Clavel, F. T. B. (ca. 1845)
- Clawed Frogs and Surinam Toads: Pipidae
- Claymont Society for Continuous Education
- Cleanthes of Assos
- Clear Light (Magazine)
- Cledonism (or Cledonismantia)
- Cleidocranial dysplasia
- Cleidocranial Dysplasia
- Cleidomancy
- Clemens von Pirquet
- Clément Ader
- Cleromancy
- Cleveland Clinic 3-Day Diet