The small Westphalian village of Morwede seems a humble beginning for Dr. Amberg's medical career, but here he has an experience that alters his career forever. Ruled in 1932 like a feudal holding by Baron von Malchin, Morwede is the crucible for the baron's experiments with Saint Peter's Snow, a parasite-cum-hallucinogen. This drug's awful effect on the peasants, however, is as uncertain as the story Amberg tells. Recovering in the hospital after an auto accident, he discovers he may have lived this novel's story only in delirium; or is everyone's denial of the truth simply proof of conspiracy? Banned for political reasons when first published in 1933 Nazi Germany, Saint Peter's Snow ranks with 1984 in its portrait of a manipulated populace. Though he died in 1975, Perutz's writing remains significant today.-- Paul E. Hutchison, Pequea, Pa.