THE RECENT phenomenon of a few writers (Gay Talese, Judith Krantz, E. L. Doctorow) signing book contracts for millions of dollars appears to have given rise to the common misperception that all writers are now able to afford, for example, cars that cost what houses used to. It just isn't so, certainly not among most of the Washington writers I spoke with recently. As one local writer put it, "Just because O. J. Simpson gets a huge amount of money doesn't mean that every poor slob in the line is equally well paid."

Larry L. King, who has parlayed a magazine piece ("The Best Little Whorehouse in Texas") into the beginnings of an empire, said, "Back in '65, when I sold my novel [The One-Eyed Man ] for the pitiful amount of $1,500, there was the automatic assumption on the part of everyone who knew nothing about the book business that I was rich from that moment forward, whereas the truth was that I was not. Most writers are not rich. The Authors Guild did a survey about 10 years ago, and the results showed that the average writer made about $7,000 a year."

Just as I was on the verge of feeling sorry for King, he added, "The most I ever made, prior to 'Whorehouse,' in a single year from magazine pieces, books and lecturing was $70,000. The average was $45,000 to $50,000."

An average of such magnitude, even today, would probably satisfy the aspirations of most writers. Phyllis Theroux (California and Other Sates of Grace ) said, "I've made more money from writing than I ever thought I would, but just today I took delivery on a load of wood and had to ask the man if I would pay him in installments."

In a similar vein, Abigail McCarthy said, "People do think you get more than you do because they hear of the half-million-dollar advances. But I'm horrified to find how little fine writers actually get. Take someone very talented, like Susan Shreve, for example, who has written four novels and teaches in the creative writing program at George Mason University. Frankly, I don't see how young writers can survive."

One of the most detailed explanations of why all that glitter does not turn into solid gold for the writer was provided by a man who did receive one of those big, well-publicized paperback contracts -- Less Whitten. A journalist now associated with Jack Anderson only on a part-time basis, Whitten had written several novels, but the one that struck it big was Conflict of Interest, the story of an investigative reporter. Doubleday paid him $31,000 for the hardcover version, and then Bantam, at auction, bought the paperback rights for $360,000.

"That's a huge amount of money, and everybody thought I got it all. But Doubleday got half off the top, and they also took back half of the original $31,000 that hadn't been earned back yet. Also, my agent took his 10 percent, that's another $18,000 -- and then came the taxes. The book looked like it had made over $400,000, and in fact it did, but not for me. Before taxes, and without deducting all the expenses of producing the book -- typing at a dollar a page with a lot of retyping involved, Xeroxing, travel, etc. -- I probably made about $175,000.

"It's funny, all my neighbors thought it was great that even though I was now 'rich' I still stayed in the old neighborhood, when in fact, what with taxes and kids in college, I couldn't have afforded to move. Now don't get me wrong. It looked like a nice chunk of dough and it was; but it wasn't the fortune so many people thought it was."

Perhaps the saddest story about book profits is that of Washington Post Magazine columnist Rudy Maxa, the author of two books, one of which was Public Trust, Private Lust, coauthoried with the late Marion Clark. Clark had been his editor on The Post Magazine and helped break the Elizabeth Ray - Wayne Hays story.

"We got an advance of $30,000 to split -- though a lot of my friends somehow got the idea the money was all mine -- and after my agent's 10 percent and my expenses, I had about $7,000. But I had taken off time from work, which cost me over $6,000 in salary. That left me almost $1,000 to the good. Then Marion talked me into having the book party, which we paid for (the publisher sent down 20 free copies of the book) at F. Scott's in Georgetown, with an open bar featuring ice-cream drinks and Chivas Regal! The bill for the party came to more than $2,000, so I lost money by writing the book."

One author who has not run across the public misconception that a book contract means great wealth is critic-novelist Doris Grumbach, whose third novel, Chamber Music, was not only well received by reviewers but also had a good sale. "I never thought of writers as being rich, and I don't think anyone of any sophistication does. I did make more money than I had expected to, which is nice, but while you may have a sudden good year, a long drought can then set in. Unfortunately, the only people who are blissfully unaware of this is the IRS, which allows you to income average back, but not forward. Of the money I made from Chamber Music, I paid 51 percent in taxes."

Novelist Barbara Raskin also said she hadn't run into anyone who thought she was rich just because she is a writer: "People are pretty hip that there are superstar writers and that the rest of us have to divvy up a pie which is not all that big. The situation is so bad that many young writers are passing up the writing life. But the reason, probably, that I don't run into this misconception is that I've complained so much that everyone knows my position."

Also in agreement is Patrick Anderson (author of four novels, including The President's Mistress, which sold to paperback for $250,000). "People should understand that a book contract is not paid out all at once, but usually in thirds. [One-third at signing; one-third at acceptance, which is another story; and the final third at publication, a process that can and often does take years.] And then if you get a paperback sale, that means only one-half goes to you, and that half is also often paid out in thirds. But, I live in the country [Waterford, Virginia] and the people here know me, see me going around in old clothes and driving my 15-year-old car. "They don't think I'm rich."

One of Anderson's writer friends is Joseph C. Goulden, author of 10 books of nonfiction, one of which -- The Superlawyers -- was on the New York Times best-seller list in 1972 for 27 weeks and has sold, in all forms and languages, some 7 million copies. It made him a rich man, temporarily.

"You get that initial wad and you think, 'What can I do with it?' and you forget entirely about the typewriter; I bought some properties with my Superlawyers money, a number of which I've since sold. A book contract is capital you can draw on, but expenses eat up a lot. On my Korea book [Goulden is finishing a book on the Korean War, which his publisher calls "The Pentagon Papers of the Korean War"] I've spent $7,000 on Xeroxing alone! And it doesn't take long to drop $30 for bourbon while interviewing a retired admiral or general at the Army-Navy Club. I'll tell you, that big advance may look great, but it's a long time till the next payday."

Novelist and rare-book dealer Larry McMurtry (who spends half his time here and half in Texas) says that people do not think he is rich because he has written so many books. But they do think the sale of several of his books to the movies has brought him fabulous wealth.

"It wasn't until the late '60s and early '70s that producers started giving the author a percentage of what the movie made. Consequently I got no percentage of Horseman Pass By , which became Hud , and nothing for The Last Picture Show. Now Last Picture Show has made about $30 million, for the people who made the movie. From the same book I made $30,000 to $40,000. I do have a percentage of several other books of mine that may be made into movies, but the public has no idea how little you can make off movies. People think that if you've sold a book to the movies you must be rich, but that isn't true. I know, because I'm not."

And yet, as we all know from reading the papers and listening at parties, some writers do make a great deal of money from time to time, and there are such exceptions in Washington. One is Kitty Kelly, whose profits from Jackie Oh! helped to buy a house in -- where else? -- Georgetown. Yet Kelly does not sound entirely happy: "In 1978, Jackie Oh! was the 15th best-selling book in the United States, which means that I should be running around in gold lame jeans, but that isn't so."

Still, the success of that book got her a $600,000 advance on her current project, a similar-style biography of Elizabeth Taylor. (Indeed, sme wag put up a sign outside Kelly's new house which read, "This is the house that Jackie Oh! built and Liz Taylor will furnish.")

Kelly might well sympathize with Bruce Cook, author of the novel Sex Life , and a frequent contributor to Book World . Cook discovered that a carpenter working on his Washington home was "reevaluating the length of the job, to his advantage, because he'd seen books and magazines around with my name and byline on them. We had to have a talk and sort it out. I learned that he also believed my ancient Corvair was actually a sports car and far more valuable than his own late-model Cadillac."

"But," countered journalist-author Milton Viorst, "most people I know are writers, or close enough to writers to realize that just because Gay Talese gets a million-dollar contract all writers are not rich. My experience is that the publishing business is going to hell and that the contracts -- all contracts -- aren't as easy to come by."

Looks can be deceiving. One writer admitted that even though his book had been on The Post's Washington best-seller list for 21 weeks, it had sold only 12,000 copies.

Certain comments stick. Trevor Armbrister, who is now with The Reader's Digest and who ghost wrote Gerald Ford's book A Time to Heal (but whose name does not appear on the title page because his editor at Harper & Row said to do so "would not be presidential") free-lanced for a long time before writing the Ford book or his other best seller (coauthored with Don Riegle, O Congress. He said, quietly, "I'd been poor for so long."

And Andrew Tully, who holds the unusual distinction of having had both a novel and a work of nonfiction n the best-seller list at the same time (with Capitol Hill and The Inside Story of the F.B.I., in 1962) said, "There was a lot of kidding about when is Tully going to buy a yacht, but it eventually died. I guess I could give up my newspaper column and still live comfortably, but, I'll tell you, I'm from New England, and up there we never like to tell people how much money we have."

Many writers are not good business people. But some are, and some have learned to be. Kitty Kelly and Joe Goulden and Garrett Park's Paul Dickson warn about the importance of reading all the clauses in the standard book contract. Many mistakes have been made along these lines, for writers, like readers of magazines and newspapers, are often misled by the sound of money.

One writer, who begged not to be identified, or rather, begged that her banker not be identified, said she'd been offered a mortgage loan she could not really qualify for based on present income because the loan officer at the bank saw an ad for her book in The New York Times. "He was seduced by pure potential."

So, every once in a while, the misperception works to the writer's advantage. As for this writer, who has been involved in a couple of big-money books as a collaborator, I don't have to worry. My plumber friend also does work for Jack Anderson, which means that he knows what real money looks like.