There were no robber barons among the U.S. Auchinclosses, dour Scots Presbyterians who established themselves in Manhattan in 1803, and each generation either made or married its own fortune (the author's wife is a Vanderbilt). Since Auchincloss has, of course, already chronicled the clan in his novels, what he does here is to fill in the missing blanks: The Rector of Justin (Groton), he tells us, was modeled on Judge Learned Hand and not, as assumed, Endicott Peabody. But it's money that primarily occupies Auchincloss in this tony autobiography -- he's that well-bred breed of snob who seems not to suspect he might be one (witness his comment that anti-Semitism was so casually accepted by his class that his own generation in turn was able to discard the prejudice just as casually) -- as he explains that like most children of affluence he grew up thinking his family only tolerably well fixed. A winter townhouse, a Long Island summer house with a year-round caretaker, a place at Bar Harbor, two nurses, a cook, kitchen maid, waitress, chambermaid, chauffeur and four automobiles -- all maintained on a piddling $100,000 a year (remember, though, that was 1927). Auchincloss is at great pains to refute the critics' charges that his novels, patterned as they are on the wealthy, are limited. Not so, answers the author; although he writes about the milieu he knows best, his themes are universal. But as Hemingway once quipped: the rich are no different, it's only that. . . .