CROSS-COUNTRY SKIING RIGHT by William Hall (Harper & Row, $12.95). The Professional Ski Instructors of America have named this their official book for cross-country skiing because it covers both learning and teaching techniques commonly practiced by the pros. The American Teaching Method avoids dictating what's right or wrong; instead, it advocates using thought processes that we used as children. "As adults, we have almost lost this natural ability to learn," Hall writes, adding, "We tend to think too much before we move." The basics are all here: buying the right equipment, waxing, care and repair, and a few physical exercises you can do while waiting for the first snowfall. The text is entertaining, with helpful diagrams and photographs. At the beginning of each section there's a photo and chapter heading followed by an insightful quote from such notables as William Hone, James Thurber and Lars Larsen. One by Larsen on "The Overnight Tour" advises, "Don't let being lost take the fun out of not knowing where you are." Larsen's advice holds true to the reading of this manual as well. Don't feel you have to read every bit of it before you ski this winter--it's an overwhelming source of information. If you're a novice, just read the part on "Learning Right" and rent some skis. Hall advocates gradually working your way into cross-country skiing. Start now by trying the exercises that he describes, then use some of the techniques when you ski. You'll be an informed skier starting out with some of the best instructions around.