BOOK REVIEW : A Telling Dialogue of Writers : FLAUBERT-SAND The Correspondence Translated from French by Francis Steegmuller, Barbara Bray ; Alfred A. Knopf; $30; 435 pages

After her first visit to Croisset, Gustave Flaubert’s river-side retreat in Normandy, Georges Sand wrote him: “Great man as you are, you are a good kind boy and I love you with all my heart.” She also announced the dispatch of a set of her complete works. “Just store it away on some shelves in a corner,” she advised, “and dip into it whenever you like.”

“It” was 75 volumes; to dip into it was the equivalent of taking a ladle to the sea. It came from a woman who regularly turned out a novel in three months, working mornings only; to a man whose mania for a bare and purified style had him crossing out two words for every one he wrote, and suffering abysmally all the while.

The comic tactlessness of the gift is the aptest of symbols for one of the most nourishing and beguiling marriages of opposites in 19th-Century literature. Sand was in her early 60s when they became friends; a flamboyant relic of the high romanticism of the first half of the century, lit by the aura of her revolutionary past and her stormy life and loves.

At 45, Flaubert, chafing in the tight collars and bland materialism of the Second Empire, was an irascible cynic with a flaming zeal for cold objectivity.

The relationship was entirely platonic, yet passionate, nonetheless. It was the comradeship of two artists-eccentrics, the willingness of two formidably assertive characters to confide their weaknesses to each other, a mother-son bond with a daughter-father tinge here and there; and all in all, a union of hearts. A phrase that Flaubert, unlike Sand, would never have consented to see in print.

“A novelist hasn’t the right to express his opinion on anything whatsoever. Has God ever expressed an opinion?” he demanded. To which Sand, who thought of herself more modestly as Creation, not God, replied: “Not to give the whole of oneself in one’s work seems as impossible to me as weeping with something other than one’s eyes or thinking with something other than one’s brain. What did you mean?”

The correspondence between Flaubert and Sand was collected and in 1981 edited by the French scholar Alphonse Jacobs. Now, Francis Steegmuller has rounded off Jacobs’ work for the American reader, collaborating with Barbara Bray in a translation, and supplementing Jacobs’ notes with a foreword and bridge passages of his own. He has made available to us, not only the wonderfully revealing Flaubert-Sand dialogue, but also the quiet attentiveness of the scholar, now deceased, who dedicated his life to it.

The more than 400 letters written between 1865 until Sand’s death 10 years later give a privileged access to their great argument. Sand’s life was, in a way, her work--although these letters, more than most of her novels, show what a superb writer she was--and Flaubert’s work was, of course, his life. She will argue incessantly for a connection between the two; he, for a separation.

Throughout, Sand pays tribute to Flaubert’s talents and deprecates her own. Her work was popular, commercially successful and condescended to by the literati. He was respected artistically--although widely criticized for his later books--and, apart from “Madame Bovary” and “Salaambo,” he barely sold.

“I love life too much to be a litterateur ,” she writes. “I’m more amused by the condiments than by the dinner.” For his part, Flaubert details the agonies he suffered for each line. “Everyday I chip away at my coconut like a convict breaking stones. I’m one myself. Not a convict. A nut.”

After reading one of her full-blooded historical novels--he seems to have liked them for her sake, if not for their own--he complained how hard he was finding it to strip his later work of such extraneous matters as authorial emotion and vibrant protagonists: “Manipulating such lightweight characters is a heavy task.”

Sand worried that this monastic austerity would dry him up. Unspoken, but implied, was the thought that it would dry up his art as well. She urged more exercise--thinking, she argued, “takes place in the legs, as well.”

She found in him an immense childlike ability to take pleasure in people and things. On her visits to Croisset they would go for excursions and stay up until 4 in the morning talking. They referred to themselves as each other’s “troubadour.”

She helped him deal with his publishers; he helped her deal with the Napoleonic court, where he had connections.

They quarreled, though never personally. She believed in the People, while he despised them. “If you could only hate! That’s what you lack: hate,” he wrote. “Despite your great sphinx eyes you have seen the world through a golden haze.” To which she replied that “chronic indignation may be an organic necessity for you. It would kill me.”

Yet, he admitted to a friend: “Her serenity is contagious.” And after her funeral, he said that he had buried his mother twice.