Letters of the Law THE LAW FIRM of Sullivan & Cromwell was a bit of a sweatshop back in the late '40s. That, at least, was the accusation people made to senior partner John Foster Dulles.

"Not at all," Dulles would reply in his imperious way, pointing out that his staff had vast amounts of leisure time: "I understand they write novels."

Well, one of them did -- and still does. Before there was Scott Turow, before Scott Turow was even born, Louis Auchincloss was practicing law and writing fiction at the same time. Over the decades he has produced several dozen novels, short story collections and works of non-fiction, nearly all of them while working first at Sullivan & Cromwell and then, from 1954 until his retirement in '87, as an estate and trust specialist at Hawkins, Delafield & Wood.

Auchincloss's production has been so regular that there's a tendency to either dismiss him or take him for granted. The only Auchincloss title most readers could readily name is The Rector of Justin. That 1964 bestseller about a soon-to-retire headmaster at a New England prep school, commonly regarded as his most ambitious novel, is considered by Auchincloss himself as "perhaps my best work, unless perhaps The Lady of Situations is it."

Is this reference to his latest, issued this summer by his long-time publisher Houghton Mifflin, merely a writer's instinctive tendency to claim that the most recent is also the best? "It's benefited by my retirement," Auchincloss feels. "I've given it more concentration, more polish and more form than the others."

Not that all those other books suffered from Auchincloss's years in the legal trenches. "Lots of writers think they have to have some silence, their slippers and a pipe, and a complete period of time," he says. "Well, they only do it that way because they're able to. What I had to learn was to take advantage of brief periods of time and write for five minutes, 10 minutes, or an hour.

"If you've never been to a rehearsal of the opera, you'd think they would start at the beginning of a scene or the beginning of an aria, but they don't. Not only do they start in the middle of an aria, but in the middle of a particular word. It's exactly as if you'd picked the needle off a gramophone and put it down in the middle of a note."

A gramophone? When was the last time you heard someone unselfconsciously use that word? But Auchincloss's speech is peppered with terms like "lese-majeste" and "tosh" that seem to come from an earlier generation, just as his subject matter -- the legal profession, the business world, life among the upper-crust -- is one that is neglected by most serious modern writers.

This hasn't helped him with the critics. "I'm so tired of people saying I write novels of manners," he says.

Just what is a novel of manners anyway? "Something about tea cups and society ladies. It's a denigrating term."

Among his best works are The House of the Prophet (1980), which recasts columnist Walter Lippmann's life in novelistic form; The House of Five Talents (1960), a sociological novel about the expenditure of a great fortune; and The Embezzler (1966), a fictional adaptation of the tremendous scandal that ensued in the late '30s when former New York Stock Exchange president Richard Whitney was caught looting funds from the New York Yacht Club.

If that crime occurred today, it would barely make it to the front page of the New York Times metro section. Comments Auchincloss: "There's no question that the financial society of the time regarded Whitney as, in that banal term, a traitor to his class. When he came out of jail, many, many of his old friends and associates wouldn't speak to him. They thought of themselves as a moral society.

"Do you think the big people in the corporate merger world think of themselves like that? I think they rather like thinking of themselves as buccaneers. It gives them a sexy feeling."

While Auchincloss's works have lost nothing in readability over the years, some of the events and attitudes recounted in them now seem as remote as those in Henry James or Edith Wharton. When he tried to write a one-act play for PBS based on his early story "The Mavericks," a simple update from the '50s to the '80s proved impossible.

"I had to do the whole thing from scratch," he says. "I might as well have been writing in the Renaissance. It was incredible how things had changed -- how law offices are run, the coming of women into the firms, the change in moral standards. The whole thing was based on pregnancy, which would hardly have bothered a young man or woman thirty years later."

Another obvious change in the last few decades is the diminished reputation of the legal profession. "It's fallen off very much, and quite justifiably," Auchincloss agrees. "All the things commonly said about lawyers are true -- they're very greedy, after the fast buck, very aggressive and pushing and so on." You can tell that's the writer in him talking -- beholden to no class or profession, even his own.Brand-New Old Books A FIRST edition is a curious thing. Take The Sun Also Rises. It appeared in 1926, when Hemingway was near the beginning of his career, so the initial press run was comparatively modest: 5,090 copies. How many of those copies still exist, with the lovely pale jacket? At most, a hundred in private hands and another hundred in institutions. The rest of them were read to pieces, left out in the rain or on the beach, the jackets slipped in the trash.

If you were lucky enough to find a copy of Sun in your grandmother's attic, with a clean and intact dustjacket, it would be worth at least $12,000. But if it weren't a first edition -- if it were a later printing or a book club adaptation -- its value would never be more than a few dollars.

This is a distinction that doesn't seem to make a great deal of sense. One can understand why a Picasso is worth millions and a poster of the same painting is worth $10, but a copy of The Sun Also Rises is at all times a mechanically produced object. It's illogical, but that's how the game is played.

Over the years there have been a number of first edition clubs. Otto Penzler, for instance, is currently running one out of his Mysterious Bookshop in Manhattan. Every month you get a signed first edition of a new mystery book. And now there's something called the First Edition Library, which you'd think from the name was doing the same thing.

Actually, this two-year-old concern specializes not in the real thing but in facsimilies of the great first editions of the first half of the century: Hemingway, Faulkner, Steinbeck and Fitzgerald and so on. Book and jacket are exact replicas of the first printing, placed in an attractive and sturdy slipcase. An accompanying card gives background on the title, publication date, dedication and so on.

It's obviously possible to criticize the First Edition Library, which currently has 11,000 members. The very name is doublespeak on the order of "genuine imitation leather": What the library is producing aren't first editions, they're imitations of the real thing. While a real first edition may grow in value, these books assuredly won't.

The funny thing is, though, the First Edition Library did its job too well. Rockville book dealer Allen Ahearn reports that on the first three titles he received -- The Great Gatsby, Of Mice and Men, and For Whom the Bell Tolls -- the dustjackets carried no notice that they were reprints. If you had a first edition of For Whom the Bell Tolls without a dustjacket, you could slip the library's on it and, voila, a $50 jacketless book becomes a $500 jacketed one.

That's apparently what someone did with a copy that a leading auction house had on consignment this spring, until it was pointed out to them that the jacket looked much too new. With Gatsby, there's an even greater potential for trouble, since the first edition would fetch $15,000 in a good jacket.

Enough talk of possible deceit. Suppose, for instance, you simply wanted to reread The Great Gatsby, to rediscover those great lines like "I usually find myself among strangers because I drift here and there trying to forget the sad thing that happened to me" and "You look at him sometimes when he thinks nobody's looking at him. I'll bet he killed a man."

It's easy to find a paperback, but a hardcover would probably have to be special-ordered from the publisher. Morever, in Scribner's plainly designed Hudson River Edition, the book looks as appetizing as an accounting textbook. But the library's jacket is the famous Francis Cugat painting that his editor Max Perkins commissioned and which Fitzgerald then incorporated into the book. With Tender Is the Night, the contrast between the boring Hudson cover and the first edition's lavish drawing of the Mediterranean is even more striking.

Books from the First Edition Library can be ordered individually for $34.95 (without slipcase) or $39.95 (with slipcase). Subscribers, who receive a book every six weeks, get them for $5 cheaper. All in all it's a pleasant way to acquire permanent editions of the classics, although the price is getting near the ceiling for this sort of thing. Call (800) 345-8112 for more information.Bite Your Tongue THERE ARE everybody else's books of quotations, and then there are Robert Byrne's. He's now produced The Fourth -- and By Far the Most Recent -- 637 Best Things Anybody Ever Said (Atheneum), which he claims is his best effort because "socially and mentally, I'm much more twisted than before . . . and therefore in closer harmony with the rest of you."

He's also relied more heavily on people making up one-liners than previously, which means that the material isn't age-tested. Some samples: "Instead of getting married again, I'm going to find a woman I don't like and give her a house" (Lewis Grizzard). "Talking with a man is like trying to saddle a cow. You work like hell, but what's the point?" (Gladys Upham). "A favorite dish in Kansas is creamed corn on a stick" (Jeff Harms). "Where there's smoke, there's toast" (Unknown).

Byrne isn't the only one with bile in his blood. That's also true of the folks in Bitch Bitch Bitch (Dell), an above-average collection compiled by Mike Wrenn and David Wheeler that is solely devoted to nasty comments.

Clive James on Marilyn Monroe: "She was good at playing abstract confusion in the same way a dwarf is good at being short." Erle Stanley Gardner to a magazine editor: "It's a damn good story. If you have any comments, write them on the back of a check." Cher on The Velvet Underground: "It will replace nothing, except maybe suicide." Katharine Hepburn: "I think it's a relief to be alive -- if you can enjoy life. And it's a relief to be dead, if you enjoy sleeping."