Mostly? Weaned on his stepfather's Fleischmann's yeast fortune, Botsford grew up in an Upper East Side brownstone with eight servants for his five family members. Deb parties, the transatlantic steamer ride to Europe, and the Yale Daily News' ''Once Over Lightly'' humor column variously made his coming-of-age to-do list. Sounds like fun... but its telling is matter-of-fact and dull. Moreover, Botsford's stories of decadence connect only in the worst way with what unaccountably precedes them, a wan chapter on his WWII infantry service (on trying to find a rendezvous in Normandy: ''Looking for him elsewhere was hopeless -- an aiguille in a meule de foin...''). At least the more interesting last half pitches intermittently gripping stories about A.J. Liebling's photographic memory or Wolcott Gibbs' acid tongue from Botsford's 40 years as an editor at The New Yorker.