THE SECRET WORLDS OF COLIN FLETCHER <i> by Colin Fletcher (Vintage: $9.95)</i>

The author of seven other books on hiking, Colin Fletcher is no blithely cheerful apostle of the out-of-doors. The tone of his reflections on trekking through various parts of North America ranges from unabashed delight in the beauties of the land to bristling misanthropy toward hikers who have the temerity to appear in areas that he’s claimed for himself. When several small parties of hunters “invade” the shore of a remote, Alaskan lake he’s staked out, Fletcher dispatches a threatening note to the owner of the air-transport service--and finds himself having to explain his actions to the local police. (He’s also careful to disguise the sites he visits, lest others discover them--which seems both understandable and spiteful.)

At his best, Fletcher communicates the special rhythm of striding along a mountain path and the serenity it imparts; at his worst, he comes across as a smug curmudgeon who travels the wilds not because he loves nature, but because he dislikes people.