THE AUDUBON SOCIETY POCKET GUIDES: FAMILIAR MARINE MAMMALS <i> by Stephen Amos </i> : FAMILIAR SEASHORE CREATURES <i> by Stephen Amos </i> : FAMILIAR BUTTERFLIES <i> by Paul Opler</i> : FAMILIAR MUSHROOMS <i> by Peter Katsaros (Alfred A. Knopf: $5.95 each, illustrated) </i>

This useful series of nature guides combines handsome color photographs with concise, practical texts. Paul Opler explains what characteristics to use in identifying an unfamiliar butterfly and offers tips on how to observe these lovely insects without damaging their fragile beauty. Peter Katsaros includes notes on the edibility of many North American mushrooms but warns the amateur naturalist of the dangers of mushroom gathering: Some members of the common Amanita family contain deadly toxins. Because so many of the animals in Stephen Amos’ guide to marine mammals are threatened or endangered, this volume has an inevitably lugubrious overtone, and Amos urges readers to note and report any sightings that may assist conservation efforts.

The books are sensibly designed in a compact (4x6-inch) format that fits neatly into the pocket of a shirt or a pair of jeans, and can easily be taken on a nature hike. Additional volumes in the series are devoted to trees, flowers, insects, seashells and fossils.