This story begins where Patrick O'Brian's devoted fans would want it to, with a sloop in the South China Sea barely surviving a killer typhoon. But the time is the 1930s, and the protagonist a teenaged American boy whose missionary parents have just died. In the company of his rough seafaring uncle and an elderly English cousin, an eminent archaeologist, Derrick sets off in search of ancient treasures in Central Asia. Along the way they encounter a charismatic Chinese bandit and a host of bad characters, including Russian agents fomenting unrest. (Most of these meet very bad ends.) The narrative--as in all of O'Brian's novels--touches on surprising subjects: astronomy, oriental philosophy, the correct identification of ancient Han bronzes, and some very local cuisine. It ends in an ice-bound valley, with the party caught between hostile Red-Hat monks and the Great Silent Ones, which is how the Tibetans designate the "yeti."  (CAS147, $14.95)