THE BEST PART OF WALKING THIS TRAIL: KNOWING WHEN AND WHERE TO GET OFF

The Pacific Crest Trail, which runs from Canada to Mexico, is generally regarded as the Western equivalent of the Appalachian Trail, which extends from Maine to Georgia, although the former is more challenging in its wild miles through the High Sierras and the North Cascades. In The Pacific Crest Trail: Escape to the Wilderness (Lippincott, $8.95), Ann and Myron Sutton make the point that the Western trail is substantially different in that, unlike the Appalachian, the main north-south route serves as a link between a number of side paths. The main trail has become so popular that, especially near highway crossings, the "traveler may encounter noise makers, litter throwers, tree choppers, shortcutters, flower pickers, polluters, vandals and lawbreakers." These can be avoided by seeking out side trips over old stagecoach routes, for example, and the many trails in the Cucamonga Wilderness. Throughout much of Oregon's Skyline Trail and the Cascade Trail of Washington, side trails branch off at intervals, providing marvelous exits to lakes, falls, hot springs, caves, meadows and beaver ponds. "There is almost no limit," write the authors, "to the exploration potential of these thousands of miles of side trails."

Ann Sutton is a geologist, her husband Myron a biologist, and their book is leisurely and discursive, with emphasis on trees, wild, flowers and rocks.

The spectacular mountain scenery along the trail is better communicated by the 125 color photographs in The Pacific Crest Trail (National Geographic Society, $4.25) taken by Sam Abell, with text by William R. Gray. The book is a pleasant, uncritical, campground-by-campground account based on the authors' own exploration.

But the most graphic record of the Pacific Crest Trail and its hardships is still The High Adventure of Eric Ryback (Chronicle Books, $6.95), published five years ago. At 17 Ryback hiked the entire 2,000 miles of the Appalachian Trail; at 18 he set out alone over the 2,300 miles of the Pacific Crest Trail from the Canadian border and reached Mexico some 130 days later. Nearly frozen at the start, suffering from loneliness, self-distrust, fear, hunger and occasional disorientation, Ryback's achievement was incredible, but it left him with no time to enjoy the wilderness the trail was built to penetrate. The Suttons are right: for those who enjoy walking, the real appeal of the trail is in the opportunity to explore what it opens up. To regard it as a hikers' highway can destroy it.