THE NATURE CATALOGUE <i> by Joel Makower (Vintage/ Tilden Press: $18, illustrated) </i> and WHAT CAN I DO TO MAKE A DIFFERENCE? A Positive Action Source Book <i> by Richard Zimmerman (Plume: $15, illustrated).</i>

Both of these volumes offer listing of organizations, exhibits, sources of literature, etc. The attractively presented “Nature Catalogue” emphasizes the pleasures of ecologically oriented hobbies and how an interested amateur can work to improve the condition of the planet. “What Can I Do?” is more political in its subject matter--and more than a little hysterical in its tone. Zimmerman champions liberal solutions to various problems, and stresses the importance of writing letters, volunteering and organizing groups. The author presents only one side of some complex issues: The section on animal rights relies almost exclusively on material supplied by PETA (People for the Ethical Treatment of Animals)--hardly an impartial source--and fails to mention insulin therapy, transplant surgery and other medical advances achieved through animal research. A self-righteous sermon to the converted, “What Can I Do?” will annoy anyone outside the flock.