Two decades ago, the years of Lyndon Johnson cracked the social consensus until the streets rang with the cries of a nation dividing. And now "The Years of Lyndon Johnson," the first volume of Robert Caro's three-part biography, has split the critics into a frenzy of factions.

The Wall Street Journal calls it "an appalling portrait -- Dorian Gray's at the end of his life could not have been more hideous." But Newsweek says it's an "awesome achievement."

The New York Times Book Review derides it as "repetitive and fiercely polemical . . . not merely negative but hostile . . . more a caricature than a portrait." But Christopher Lehmann-Haupt sees it as a "monumental political saga." And the Book-of-the-Month Club finds it "so important" that for the first time in eight years it is "urging" members to buy. BOMC's last such plea was for Solzhenitsyn's "Gulag Archipelago."

The Washington Post says "the main passion" is hatred or contempt: "Caro loathes Johnson. He despises him." But historian Barbara Tuchman calls it "superb and unique . . . meticulous in research, grand in scale."

The object of this monsoon of controversy, munching placidly on a room-service sandwich at the Mayflower, seems an unlikely target. At 47, Caro -- former investigative reporter for Newsday and author of "The Power Broker" (1974), the Pulitzer Prize-winning biography of Robert Moses -- has the mild voice and pedantic poise of a grad-school lifer. After carefully replacing his glasses (removed for photos), he settles into a chair, brings his fingertips together and, with his forefingers, begins obsessively kneading the balls of his thumbs.

The criticisms, he says in his quiet New York consonants, "are not fair. In fact, they're not true -- they're lies. The documentation is so thorough and complete that no real questions can exist in the mind of a truthful person."

"I thought I was going to love Lyndon Johnson." But after seven years of work on the first volume, which takes Johnson from his birth in the unforgiving hill country west of Austin -- out of which he came "formed . . . into a shape so hard it would never change" -- to his 1941 defeat in a Senate bid, Caro concluded that LBJ had lied consistently about a sycophantic and manipulative youth and had exploited his House seat to build a personal power base while serving as a conduit for Texas oil money. After hundreds of interviews, months of research in the LBJ Library and two years in Texas, Caro wrote that LBJ's ambition was "so fierce, so consuming that no consideration of morality or ethics, no cost to himself -- or to anyone else -- could stand before it. Once on the path to power, he had "an utter ruthlessness in destroying obstacles in that path, and a seemingly bottomless capacity for deceit, deception and betrayal in moving along it."

Not surprisingly, the book has provoked an eruption of outrage from many reviewers and Johnson partisans.

"He began with the preset view that LBJ was a monster," says former LBJ aide Jack Valenti. A "hatchet job," says James Rowe, an FDR adviser who knew Johnson for decades. "He's an investigative reporter, and they're all muckrakers -- all he's looking for is dirt."

That, says Caro, ignores a number of positive chapters. In one, he describes how Johnson dropped out of college for a year to teach Mexican kids in a dusty hamlet. "He could have got the same salary and done just the same slipshod job as anybody else." But LBJ brought such a selfless zeal and deep sympathy to his work, Caro says, that "you saw the Great Society right there."

In fact, "the achievements that people say I've slighted they only know about because of this book." Especially LBJ's war with the utilities to bring electricity to the hill country. "It took two or three years for it to sink in to me how much that meant." As a native New Yorker, Caro took electricity for granted. But after the hill people explained the crushing grind of life before water pumps, electric ovens and washing machines, he wrote a moving and laudatory chapter. "That's the most noble example of the use of government to help people who can't help themselves that I've ever heard," says Caro.

But LBJ would also use the same strong-arm tactics to achieve his worst, most selfish ends, Caro says. Long-time LBJ confidant Horace Busby thinks that's beside the point. "He's writing about what an abysmal person Johnson could be. So what else is new? Nobody ever pretended it was otherwise. What matters is what he was accomplishing, and no man ever got as much out of the system. When a man pursues these all-but-impossible tasks, it takes a very special kind of politician," and not one who is "fastidious or cautious." Caro agrees that Johnson's predatory vitality is "the thread. Whatever he did, no one had ever done it before -- both terrible things and wonderful things. There's no question that the tone of the book is very dark. But if there's more of the dark side than there is of the light side, what am I supposed to do about it?"

Reviewers often use the word "populist" to accuse Caro of bias. "I don't consider that an insult," he says. And Robert Gottlieb, Knopf's legendary editor-in-chief, calls Caro "a very old-fashioned person, impassioned and moral, more like an Old Testament prophet." The often-partisan tone and occasional self-congratulatory remarks about the scope of his research ("never before") detract from a sense of objectivity. As does his belief that such reputedly incorruptible champions of the underdog as Sam Rayburn (a 15,000-word profile of whom is inserted in the book) are no longer possible in the age of blow-dry pols courting the TV eye. "Obviously, I fell in love with Rayburn," Caro says. "They don't make politicians like that any more."

But Caro is adamant that his analysis of LBJ's 11-year career in the House -- in which he spoke rarely, introduced only five bills not directly affecting his district and supported few others -- is wholly objective. Caro concludes that Johnson "went to the most unusual lengths not to participate in the legislative work of the House." Harvard historian David Herbert Donald in the New York Times says this shows "Caro's failure to understand that the real work of the House is not done in set speeches and debates."

"He knows nothing about politics and how it worked then," says Rowe. Busby concurs: "To say that [LBJ] didn't do anything while he was in the House is preposterous. He became Roosevelt's chief lieutenant in the House. And besides, back in those times -- before World War II -- a freshman or sophomore House member would not even be recognized to make a speech."

"That's a cliche'," says Caro, who acknowledges the fact in his book. "But I took the records of 20 other congressmen who entered the House the same year as Johnson, and counted how many nondistrict, "national" bills they introduced. One had 168, another 149. Some went down into the single digits, but of the 21, Lyndon Johnson came out the lowest."

Caro concedes that LBJ, as the late Thomas Corcoran said, "got more projects and more money for his district than anybody else" and worked with astounding energy ("the guy's just got extra glands," Abe Fortas once said). But as for his fabled behind-the-scenes efficacy, Caro found after interviewing many of Johnson's congressional colleagues that he would rarely take a position on any issue. Former LBJ aide George Reedy, now a professor at Marquette University, says such interviews are untrustworthy. "One of the problems with Johnson was that he was always capable of convincing himself that the past was the way he wanted it to be," and had such a "powerful personality that he persuaded everyone around him that it was that way." He was "the goddamnest paradox in history," with "such a contradictory personality" that when interviewing people about him, "whatever you want to find, you're going to find."

That, says Caro, is just the point. Helen Gahagan Douglas, who knew LBJ long and well, told Caro she marveled at Johnson's "great inner control. He could talk so much -- and no one ever knew exactly where he stood."

Certainly that was true of the romance Caro uncovers. He claims LBJ became the secret lover of Alice Glass, wife of Texas publisher and oil baron Charles Marsh. Donald in his book review finds the evidence "thin" and castigates Caro for using only three "hearsay" sources. In fact, says Caro, there were seven sources (clearly listed in the notes), and "these aren't people who came out of any closet." They include Glass' daughter and sister, three of her closest friends and a close family acquaintance. (Not to mention LBJ's phone logs of calls to "Manners," Glass' code name for office calls.) Caro is particularly outraged at charges of prurience, since he says he suppressed much about Johnson's early amours. "I don't put love affairs in my books just to put them in." As for the Glass affair, "I don't think anything else is as character-revealing. This is a guy who thought he could deceive anybody -- and he could!"

The telephone rings. It is a Knopf official checking in on Caro's promo trek -- and bringing some news. Suddenly his feet start to do a little shuffling jig, and his voice rises an octave. "Oh, that's great! I got goose pimples. Oh, I wanted to hear that!" Off the phone, he explains that the book is selling so fast that Knopf has added a third printing of 30,000 to the 120,000 in the first two. And abruptly he turns away, swallowing hard, raising a hand to brush his eyes. "However corny it sounds," he says through a thick throat, "I want people to know the character of their president. Even if that character is unpleasant, America still has to know about it." With that printing, it will.

Not bad for the son of a Polish immigrant, a boy whose mother died when he was 11 and who learned to love language in the public library at 99th Street. Determined to write, he persuaded P.S. 93 to start a school newspaper and went on to edit the papers at Horace Mann and Princeton, where he majored in English. His writing teacher, R.P. Blackmur, felt that Caro was too fast and facile: " 'The trouble with you,' he said, 'is that you think with your fingers.' It struck a chord in me, and after I left the newspaper business, I consciously tried to slow my writing down." So he writes his first drafts in longhand with a pencil--a million words for the Moses book, millions more for Johnson. "It doesn't hurt," he says, "but you get calluses."

He went to work for Newsday in 1960 -- temperamentally ill-equipped ("I was very, very shy") and chronically prolix. He had "constant fights" with editors who figured story lengths by counting typed lines. To sneak in more words, Caro first tried wider margins ("they caught on"), then began deliberately leaving out words and putting them in with carets. Naught availed: "They'd say, 'C'mon, Bob, this is only a zoning board decision!' " (The same criticisms haunt his quote-laden, frequently repetitive books. But Caro is so fond of long-distance verbiage that "there's nothing I'd rather do than re-read 'War and Peace.' ") Although successful as a reporter (his expose' of a real-estate scam caused dozens of indictments), he had begun to chafe: "I couldn't tell people the complete truth" in its full complexity within the constricted context of newspaper writing. His plans coalesced one day while he was on a Nieman Fellowship, sitting in a class about highway construction. "All of a sudden I said, 'Wait a minute. That's not how highways get built! They get built because Robert Moses wants them built.' " He decided to write a book.

With a $5,000 advance from Simon & Schuster, he left Newsday with a newspaperman's confidence in rapid production. "We didn't have any savings, but I remember telling my wife, 'We're finally going to Europe -- I'll be done with this thing in nine or 10 months.' " Not quite. After a year on a Carnegie Fellowship, the money was running out. A year later, the Caros sold their Long Island house and moved to the Riverdale apartment they live in now. His wife Ina -- a professional historian who aided in the research and typed the gargantuan manuscript -- worked while Caro amassed the first 450,000 words. Finally, four years into the project, his editor asked for a meeting. "Anyone who wants to know how lousy it is to be a writer should listen to this. He takes me up to some very cheap Chinese restaurant at 107th Street and starts out saying how important it is, how he's read it aloud to his wife. I say, 'Fine, now can I get the other half of the advance?' He says, 'Well, you know, nobody is going to buy a book on Robert Moses -- face it.' "

His agent, Lynn Nesbit, thought otherwise. So, fortunately, did Gottlieb at Knopf, who shrank Caro's million words to a mere 650,000. The page count of 1,246, Caro is pleased to point out, is the physical maximum "that you can get between two covers." Meanwhile, he'd been working on a novel, "Powers of the Press," about an investigative reporter. (Contracted to Knopf, it has now reached 300,000 words and is still growing.) And he had decided, "quite logically," to write about LBJ. "In the Moses book I was examining how urban power worked in America. I then wanted to show how national power works. And the first thing that got me to Johnson was that no man in history ever ruled the Senate like this guy."

The first volume, he figured, would be the easiest. "I told my wife, 'We won't have to do much research on his youth and college -- every biography has it, it's been done to death.' " The published accounts and the evidence in the LBJ Library were uniformly adulatory, "but as I started looking around, people kept saying, 'Well, that's not the whole story.' " He tried to get it by interviewing boyhood acquaintances of Johnson's, but "they weren't being very open with me." Finally, the Caros moved into a house in hill country. "I realized that I wasn't understanding it," so he slept in the hills for several nights "to get a sense of the loneliness." Within a year, "they opened up to me." Including LBJ's brother, Sam Houston Johnson, who finally confided that the complimentary stories about LBJ's childhood that he'd been telling for years simply "never happened."

Eventually, Caro interviewed more than two dozen of LBJ's classmates and four professors, and evidence mounted that "Bull----" Johnson, as he was known, had lied about his grades, stolen student elections, shamelessly flattered college officials -- even succeeded in cutting a page of nasty comments about himself out of most copies of the college yearbook. "My God," Caro asked one day, "is everything untrue?" Most reporters would be in ecstasy, but "actually it was terribly depressing. Anyone who thinks I enjoy writing such things doesn't understand me or what I'm trying to do. I said to my wife so many times, 'I wish I was writing a biography of Thomas Jefferson!' "

Finally he brought it all back to his spartan office on East 41st Street, with the desk made of a board on sawhorses, the four massive file cabinets of notes and the 14-foot-long outline covering an entire wall. "Everyone who comes there says, 'I never saw anything like this.' Everything is numbered." He works in spurts. "I don't go by weekends, I just keep writing whatever's in one mood, and when I'm through with a section I take some time off." For the chapter on the 1941 Senate election, it meant 63 straight days.

He is more than halfway through the research for the second volume, and hopes to finish in two years. Next year he'll move to Washington, where his son Chase is studying business, dragging the reputation as a hatchet man begun with the first book excerpts in The Atlantic Monthly. He feels badly about them now. "Obviously, the ones they selected were the most negative," and "in retrospect they do not represent the book fairly. But the ultimate responsiblity for that was mine." And he's confident that readers will find the book more than "some cheap expose'."

But then that's what they called the Moses book -- at first. "Everybody now says 'The Power Broker' is a classic. But nobody even remembers that there was exactly the same swirl of controversy over it." Indeed: In 1974, The New York Times Book Review, in language amazingly similar to its LBJ review, called the Moses book "a polemic," with "too much emphasis on interviews and anonymous sources" and little "historical perspective." Eight years later, the book is required reading in hundreds of college courses and still selling well in bookstores.

"I should have learned my lesson then," says Caro, folding his busy fingers for a moment. "The only thing that matters is whether it's good or not. After a year or so, the reviews die away, the ads die away, and the only thing that endures is the book. The book stands."