POLITICIANS in Washington and elsewhere are somewhat used to being skewered by a sharp pen - or nowadays should the image be having a word processor dropped on their toes?For the financiers of Wall Street, this phenomenon is rarer. So, when Michael Lewis sat down to write "Liar's Poker," an inside account of affairs at Salomon Brothers that became a bestseller, he didn't have much of an example to follow. He cites "Where Are the Customers' Yachts?" by Fred Schwed Jr., a book published in the 1930s (and reprinted in 1985 by Fraser Publishing Company, Burlington, Vt.), and a more recent book, "Barbarians at the Gate: The Fall of RJR Nabisco," by Bryan Burrough and John Helyar (Harper, Row). The modern books are the printed version of a TV docudrama. They tell the story in narrative style, sometimes from a first-person standpoint. They are based on detailed interviewing. They are laced with personal observations, often embarrassing to the victims. And they can be funny. Publicists for Mr. Lewis, for instance, speak of his "wicked pen and a triumphant sense of humor." Perhaps most important from a publishing business standpoint, such books make money. Lewis, for example, figures he himself has made between $1 million and $1.5 million from Liar's Poker. Not bad for a first book. Those earnings include royalties, foreign sales, and movie rights. Warner Brothers has been negotiating with Marlon Brando for the role of John Gutfreund, the chief executive of Salomon Brothers who resigned in August after it was revealed that the Wall Street giant had attempted to corner the market on some Treasury securities. That scandal, of course, has given an extra boost to the book's sales. Over 1 million have now been sold. And the book has been translated into 13 foreign languages. "I have been very fortunate," admits Lewis over breakfast. A graduate of Princeton University and the London School of Economics, Lewis has a boyish look which belies his ability, as the publicists say, to "savage" many of the "most venal and foolish investment bankers and corporate raiders" of the 1980s. Lewis was on tour to publicize a new book, "The Money Culture" (Norton), which is really just a collection of previously published magazine or newspaper articles dealing with the foibles of Wall Street. "You didn't think you had written a book, and you had," notes Lewis. Since he is an amusing writer who knows the ins and outs of Wall Street, some of the articles are fun to read. Another book of the docudrama genre, James B. Stewart's "Den of Thieves" (Simon & Schuster) has been making waves. It deals with such Wall Street villains of the 1980s as Ivan Boesky, Dennis Levine, Martin Siegel, and Michael Milken. Alan Dershowitz, the contentious Harvard University law professor hired by junk-bond king Milken to seek a lighter jail sentence, has been buying full- or half-page ads in the New York Times to challenge the Stewart book's account of an alleged insider-trading episode inspir ed by his client. Last week Mr. Stewart and Mr. Dershowitz also engaged in a lengthy op-ed page exchange in the Wall Street Journal, where Stewart is page 1 editor. One trouble with such books is that it is difficult to judge whether they are fully accurate. They are usually based on interviews with close observers or participants, sometimes unnamed, in the action. But these people often have axes to grind or can misinterpret events and statements. Turning this reportage into a narrative can cause some distortions and exaggerations. In the case of "Liar's Poker," Mr. Gutfreund denied some of the incidents in the book. But his successor, Warren Buffett, has said he thinks the book is all true. For this writer, the Dershowitz defense of his client was not persuasive. But others could decide the opposite. In any case, such writers as Lewis and Stewart perform a useful role in poking at the swelled egos and twisted ethics of some Wall Streeters. It may be modern muckraking and not always kindly. But these authors are dealing with people whose obsession with chasing a buck has resulted in bilked individuals and institutions and damaged corporations.