Encyclopedias, Almanacs, Transcripts, and Maps
- Recreation in and on Freshwaters
- Recreation in and on the Oceans
- Recreational Uses of Water
- rectangle
- Recyclables
- red admiral
- red blood cell
- redcurrant
- Redgrave, Sir Steven
- redshank
- Redwoods
- Reference Works
- Refineries
- Refining, History of
- reflex action
- reflexor
- Reformation
- Refrigerators and Freezers
- Refuse-Derived Fuels
- Regan, Tom [Thomas Howard] (1938 – ) American Philosopher and Animal Rights Activist