A Little Learning

''Only when one has lost all curiosity about the future has one reached the age to write an autobiography.'' Waugh begins his story with heredity, writing of the energetic, literary and sometimes eccentric men and women who, unknown to themselves, contributed to his genius. Save for a few pale shadows, his childhood was warm, bright and serene. The Hampstead and Lancing schooldays which followed were sometimes agreeable, but often not. His life at Oxford - which he evokes in Brideshead Revisited - was essentially a catalogue of friendship. His cool recollection of those hedonistic days is a portrait of the generation of Harold Acton, Cyril Connolly and Anthony Powell. That exclusive world he recalls with elegant wit and precision. He closes with his experiences as a master at a preparatory school in North Wales which inspired Decline and Fall.