FLAUBERT is 36 at the beginning of this second volume of his letters. The scandal, trial, and triumph of Madame Bovary, his eight-year affair with the bluestocking siren Louise Colet (whom he called his "Muse"), and the 1849-1851 trip to Egypt and the Near East with Maxime DuCamp are behind him. The major events of a lifetime are over. But because the letters of a great writer are the communicated record of his inner life and a diary of ideas sent through the mails as well as a chronicle of day-to-day events, these new letters have the same fascination and compelling narrative drive as those in the first volume. That is a tribute not only to Gustave Flaubert but to Francis Steegmuller, who has translated and edited the letters with exemplary care and cast so wide and knowledgeable a net around them that they generate the excitement of a suspense story.

Flaubert is, throughout, mainly at Croisset, a southern outpost of Rouen, in Normandy, living alone with his mother in the house in which he was born and in which he was to die. It faced the Seine and the exhilarations of the Atlantic, and sometimes merely its fogs. Paris was the other end of the Flaubertian line, with its Sunday literary salons (Zola, the Goncourt brothers, Turgenev, Huysmans, de Maupassant, Daudet, and Henry James were frequent visitors), its court life, and its theater. A genius commuter, Flaubert was drawn to the rails in despair at the boredom of a backwater only to hurry home in stupefaction at the brainlessness of a city. For the most part, he preferred to stay put. Croisset was the center of his work and the touchstone of his emotional life.

The Flaubertian compass was seemingly small, but the storms that raged outside and within were equally violent. If the absence of the steamy letters of the first volume to Louise Colet makes itself felt, we miss them for another reason: they were the emotional blueprints to the inception, composition, and inner processes of Madame Bovary. No unquestionable masterpiece, with the exception of Three Tales (1877), was to follow. Luckily for us, as well as for Flaubert, the "Muse" has a Platonic successor in George Sand, who, without being able to elicit mash notes of supreme literary importance, was more intriguing in every way. George Sand is the heroine -- or, as she would probably preferred to have been called -- the hero of these letters.

And how she will surprise most readers who know only the stereotyped version of her as the cigar-smoking lover of de Musset and Chopin! She and Flaubert could not have been more different. She was fluent, expansive, with a gift for narrative and romance as natural as it was copious. She produced over a hundred books in her lifetime and was the temporary adherent of various forms of feminism and socialism. Flaubert's detachment, his perfectionism, his struggle with page after page of prose were as foreign to her as her fluency was to him. Yet they came to adore each other in a relationship of natural sympathy -- a relationship conducted at long distance between two literary intelligences who could never be reconciled to each other's point of view. The portrait of George Sand is completely sympathetic and, for the most part, self-drawn, for her letters are included along with those of Flaubert.

Charmed by the woman, and an admirer of her work on a necessarily selective basis, Flaubert was less taken with the doctrinaire side of George Sand, who took up and abandoned so many causes. She had been a pamphleteer in the revolution of 1848; he was a misogynist who went so far as to write, "As far as literature is concerned, women are capable only of a certain delicacy and sensitivity. Everything that is truly sublime, truly great, escapes them." Yet George Sand's intelligence was a match for Flaubert's, and, in one splendid rebuttal she felt important enough to publish rather than send, she outdoes him. It appeared under the title of "Reply to a Friend" in Le Temps and is translated in full by Steegmuller and printed as an appendix. It is a marvelous letter both as an essay of pure style and for what it says; overall, however, Sand's communications get a bit sticky with their upbeat humanism, genuine but tiresome, just as Flaubert's endless complaints about the impossibility of the task before him (chosen, always, by himself) become habitual and occasionally tedious, too. Flaubert, agonizing over every word, referred to Salammb.o as "an erection . . . by dint of self-flagellation and masturbation" -- a sexual image he used more than once to describe the progress of his work.

He was a greater writer and a greater thinker than George Sand, a fact she and the world recognized, but she had strings to her bow that were out of Flaubert's ken: she was famous as a lover, was a happy and dutiful mother and grandmother, and her house in Nohant (the great setting and comfort of her life) overflowed with children, lovers, ex-lovers, friends, and dogs. Neither could have lived the other's life for a moment, and it remains a wonderful source of human mystery to think they were so mutually drawn to each other. If Louise Colet had been sensuous to that perfect degree where manipulative pornography and an affair of the heart are difficult to distinguish, George Sand equally eludes being pigeonholed. She may have been the purveyor of some of the more fashionable ideas of the 19th century, but she was also as good-hearted and generous a comforter to the forlorn as one can imagine. From the evidence of these letters, she is a writer in need of rediscovery.

That George Sand is able to dominateea book that has for its background the Franco-Prussian War is a tribute to her power. Both writers suffered the imbecilities and cruelties of that misbegotten conflict. During the horrors of the Commune that followed, when French fought French, Flaubert's house was occupied by German soldiers, and the world we see of France at the time has something of the crisscrossed purposes of present-day Lebanon. Flaubert became more embittered. George Sand went on being hopeful -- an odd composite of Clara Schumann, George Eliot, and Golda Meir.

Flaubert emerges from the letters as a salty mandarin who felt betrayed as well as shocked by the vulgarity of his times. One sentence sums it up: "The entire dream of democracy is to raise the proletariat to the level of bourgeois stupidity." For democracy, however, Flaubert had no clear antidote. A cast of natural aristocrats somehow beautifully qualified to rule the world (and especially France) is what he would have preferred -- a notion as unreal then as it is now.

Flaubert's deepest feelings were reserved for a friend of his youth, Alfred LePoittevin. Because of LePoittevin's early death, their friendship was one of those adolescent crushes that remain fixed in amber. And it was LePoittevin's love of the East that Flaubert shared as a boyish enthusiasm. (This was after the years of being a child voyeur in the dissecting room of his father's hospital, in Rouen, and after the epileptoid seizures, now more properly seen as hysterical episodes, that kept him safely at home, interrupting his law studies, which he detested. A writer is all he ever wanted to be.) Enthusiasm for the East persisted in the adult, led to the trip to Egypt with DuCamp, to the travel journal (as edited by Steegmuller, Flaubert in Egypt, one of the best travel books ever written), and to the oddly unsympathetic novels Salammb.o (1862) and The Temptation of Saint Anthony (1874). We know only the third and last version of the latter; the first was withdrawn after the totally negative reactions of the young LePoittevin and DuCamp. Flaubert never wanted to write the same kind of novel twice and never did. L'Education Sentimentale (1879) was the only other "modern" novel he ever wrote. That Flaubert should be eternally dubbed a "realist" when he was drawn to the epical and the exotic is one of literature's ironies. Madame Bovary was an impediment to a more grandiose vision and needed to be got out of his system. It was while he was in the East that his most famous novel became clear to him as an emotional constellation of place and feeling--as distinguished from a "plot" or a "story"--a floating world that needed only to be anchored to a specific incident, which was supplied soon after his return. The Carthage of Salammb.o and the ancient world of The Temptation of Saint Anthony coalesced in his study at Croisset just as Madame Bovary had taken hold on the Nile. Distance was a necessary ingredient of his work, and perspective rather than "realism" is the key to it. Still, the ironies pile up. No one pretends that any of the other novels were masterpieces on the order of Madame Bovary, though L'Education Sentimentale has partisans as distinguished as its detractors. The letters we deal with, all post-Bovary, cannot transfuse life into the novels themselves, each a failure in its own way even to the sympathetic eyes of Sainte-Beuve, the Goncourt brothers, and Turgenev.

Flaubert worked on Salammb.o, "a richly colored historical and imaginative reconstruction of a vanished civilization," from 1857 through 1862, and made a short visit to Tunisia to renew old impressions of Carthage and to confirm facts. No one was more conscientious in research: Flaubert read 1,500 books as background material for his "Homeric tale," described by Guy de Maupassant as "a kind of opera in prose." Flaubert made one other trip during the period these letters cover, to England, perhaps to renew his long-term but widely spaced liaisons with the Englishwoman who was his niece's former governess.

Salammb.o was hardly what the enthusiastic audience of Madame Bovary expected. It -- along with The Temptation of Saint Anthony and even L'Education Sentimentale, set in the Paris of the 1840s -- required not only prodigious feats of research but of attention. One Flaubert letter, refuting the "facts" in Sainte-Beuve' three-part review of Salammb.o, is superb, but a second letter to one G. Froehner, an assistant curator in the Department of Antiquities at the Louvre, is a masterpiece of understated wit and malice, refuting point by point the academic objections raised. Flaubert had defended Madame Bovary in a court of law; Salammb.o was defended privately but to no less effect. Sainte-Beuve and Flaubert remained friends -- neither was vengeful. Through misplaced arrogance, M. Froehner has achieved immortality.

After Salammb.o, Flaubert was torn between two conflicting projects, a modern novel, which became L'Education Sentimentale, and another about his "two copy clerks" or his "two troglodytes" (ultimately the unfinished Bouvard and P,ecuchet), an oral history of the inane molded into novel form.

The saddest letters are those to Flaubert's niece Caroline, whom he adored. She was brought up by Flaubert and his mother after his sister died giving birth to her. But he gave Caroline some disastrous, middle-class advice: "I'd rather see you marry a philistine millionaire than an indigent genius" -- an opinion worthier of Bouvard or P,ecuchet than of Gustave Flaubert. She took his injunction literally and, years later, when her husband became virtually bankrupt, he dragged Flaubert to the brink of financial ruin at a time in the writer's life when he had the right to an earned security and at least an outward show of calm. "Respectability" and "honor" were sometimes surprisingly interchangeable concepts to Flaubert, in part a nicety of sentiment, in part ordinary bourgeois shame and pride. His entanglement with Caroline and her husband grew uglier and led to the break with Edmond Laporte, one of his few remaining lifelong friends. Out of loyalty to Caroline, and possibly as a result of inaccurate information, this painful rupture did nothing to sweeten the last years of Flaubert's life, already darkened by accumulated grief at the death of many friends and the ambiguous, sometimes hostile reception of his late work. The whole affair is a sorry one; for once in Flaubert's life he was morally compromised from the beginning in wanting for Caroline a security neither worth having nor possible to have.

Flaubert is still too often referred to as the high priest of art for art's sake, tearing his hair out as he revised yet again a sentence already refurbished a hundred times. Like all celebrated notions of the famous, this single-minded notion is a half-truth. These new letters qualify once more our impressions of Flaubert without diminishing his commitment to the art of the novel. A compulsive worker, Flaubert was also, among other things, a romantic yet hard-headed partisan of "justice," by which he meant something closer to "standards." How one behaved, the quality of one's work, the integrity with which one countered the world's flatteries and seductions were inviolable tests -- tests Flaubert often failed himself. This moral starchiness had nothing whatever to do with sexual prudery -- as anyone who has read Flaubert in Egypt would know. Flaubert's sense of values was based solely on excellence -- high levels of achievement, splendor of spirit, and purity of motive and action. In so intellectually sophisticated a man, uniquely combining traits of the peasant and the aristocrat, innocence lurks behind the great pronouncements (as a certain naivet,e lies behind the work of any artist), and, along with the innocence, a great deal of confusion. Flaubert's political "ideas" do not inspire confidence; inconsistency is their true hobgoblin. But he is infallible on literary matters and refreshing and profound when he thinks spontaneously. These letters can be read not only for what they reveal about Flaubert but as a book of wisdom. We have, in the guise of letters, what comes close to being a full-fledged biography and is, unmistakably, an incomparable handbook on writing.