As the autobiography of a former New Yorker and PM editor, Point of Departure has all the requisite exuberance but surprisingly little of the expected sophisticated elan. In fact, there's a decidedly boyish aura about the whole business, possibly because these memoirs leave off somewhere in the author's early thirties. At any rate, Mr. Ingersoll writes with a gay, modish irreverence, mostly detailing that famous decade after the First World War. Its fads and fancies, its dreams and deceptions, and anyone so interested will get an easily confidential, innocuously entertaining once-over. Coming from the dashing Goorgian McAllisters and a stuffy New England clan, Ingersoll grew up with double loyalties, paving the way for drinking, wenching and cribbing at Yale: Harry's Bar, the Riviera and first-love Constance on the wanderjahr afterwards, and setting down to mistress Julie and Bohemia inter. He breaks from this traditional mold by rough housing for a while as a Hearst reporters then he meets the legendary Ross and helps him launch what became the American Punish. They both had a high time and in the telling of it Inger-soil lets madman Ross steal the whole show. That volatile figure and his magazine's early vielselludes make Point of Departure something more than just the usual spirited personal chronicle.