Henry de Montherlant’s name doesn’t appear in the 2007–2008 program of the Comédie Française, the national French theater. His principal publisher, Gallimard, has allowed the Pléiade edition of his complete works to go out of print. No such thing would have seemed possible as late as 1990, the year when the second volume of Pierre Sipriot’s exhaustive, tell-all biography, “Montherlant sans masque,” was published. Since 1942, when his “La reine morte” (“The Dead Queen”) had its premiere at the Comédie, his plays have had pride of place on its stage, alongside those of Racine, Corneille, Molière, and Beaumarchais, and Paul Claudel and Jean Giraudoux, among the moderns.

To be sure, the repertory program at the Comédie was abandoned in the 1970s, so that one can no longer count on being able to see plays that had previously been its staples, and all of Montherlant’s fiction is still available in French in Gallimard’s Folio pocket book edition. Nonetheless, it is evident that the wheel of fortune has turned, and Montherlant, as well as his almost exact contemporary and school friend, Louis Aragon, and other superb French writers no more than 10 years older, such as François Mauriac, Roger Martin du Gard (both Nobel Prize winners), and Georges Bernanos, are suffering a real decline in popularity. Have their reputations also declined? Certainly not among French readers who know their work, or among French literary critics capable of looking back beyond the fashionable novels of Michel Houellebecq. But for an author, the loss of readers, if it continues, is like a death sentence. In Montherlant’s case, the time has come to lodge an appeal.

Montherlant was born April 21, 1895, in Paris, into a family of fairly rich, but, from a genealogist’s point of view, obscure French nobility. His father — a royalist and reactionary to the point of despising the post-Dreyfus Affair army as too subservient to the Republic, and refusing to have electricity or the telephone installed in his house — lost most of the family’s fortune speculating on the Paris Bourse. He died in 1914, unmourned by the family, and having communicated to his only son little beyond his taste for equitation and setting oneself in contemptuous opposition to society. Montherlant’s mother — sickly, her life governed by an exclusive passion for her only child — died one year later. That left Henry’s maternal grandmother. She and two weirdly eccentric uncles, both present in Montherlant’s novel “Les célibataires” (1934; “The Bachelors”) continued to live with Henry in the family’s Neuilly villa.

Henry was as much the center of his grandmother’s life as he had been of his mother’s. His grandmother was a remarkable lady, an aristocrat of great moral rectitude who, though devoutly Catholic, did not blink when Montherlant told her the almost unfiltered truth about his passions for young men of his age, or preferably younger, or when he enlisted her in his relentless efforts to promote himself. The former led to his expulsion at age 17 from the Catholic school he was attending as punishment for a “special” friendship with a younger student; the latter led to endless machinations to promote his reputation for bravery in Parisian society after he had volunteered for limited military service during the last two years of the war, and to obtain for himself a decoration, the Croix de Guerre if possible. In that effort, he and his grandmother failed.

The homosexual encounters in the Catholic school, the priest who competes with the protagonist, Alban de Bricoule, for the affections of a younger boy, and the relationship between Alban and his mother, are the subject of a moving and bold novel, “Les garçons” (1969; “The Boys”) that Montherlant worked on intermittently for 50 years. Two earlier novels, “Le Songe” (1922; “The Dream”), and “Les bestiaries” (1926; “The Bullfighters”), the first about Alban at the front during the war, and the second an account of Alban’s attempts to learn the art of bullfighting in Spain, round out the story of Alban’s youth — and to a considerable extent, the author’s.

Homosexuality was at the story’s core. While Montherlant is known to have had liaisons with women, cruising for young boys, and extended relations with them that included taking them on as servants and companions, were a constant occupation and leitmotif. Fearing blackmail if the boys he encountered on Boulevard Rochechouart and in its environs recognized him as a celebrity, he consistently refused to be photographed or to have such rare photographs of him as existed appear in newspapers. For the same reason he did not participate in television interviews, and did not use the name Montherlant in this unofficial part of his life; instead he used his patronymic, Millon.

Of course, to a great extent he was fooling himself. The police knew very well the identity of this distinguished-looking French academician — in 1960, he was elected to the Académie Française in spite of having refused to solicit votes of other academicians as required by unbroken custom. In fact, the police had orders from the prefect to avoid embarrassing him in his nocturnal perambulations. A reckoning came in March 1968. Montherlant was attacked in the street and beaten so badly about the face that he lost sight in one eye. He would live four more years, and publish another startlingly self-revelatory book, “Mais aimons nous ceux que nous aimons?” (1973, “Do We Really Love Those Whom We Love?”). The end came at four o’clock in the afternoon on September 21, 1972. Sick and almost blind in his remaining eye, this adept of Roman antiquity and seeker for happiness and fullness of life, sat down at his work table in his study at 25 Quai Voltaire, swallowed a cyanide pill, and, as precaution against failure, put a bullet in his head.

Montherlant’s biggest commercial success as a novelist was a tetralogy, “Les jeunes filles” (“The Girls”) which appeared in 1936–39. It sold millions of copies and was translated into 13 languages before the outbreak of World War II. Reviewing the English edition in 1979, Philip Larkin summed up saying

The Girls is both maddening and exhilarating, preposterous and acute, a celebration of the egotistical sublime and a mockery of it, a satire on women that is also an exposure of men, with a hero who, even as we reject him as make-believe, settles ever deeper into our consciousness.

I can’t top that except, perhaps, by happily guaranteeing the reader’s satisfaction. I will, however, add that fans of Choderlos de Laclos’s glorious “Les liaisons dangereuses”(“DangerousLiaisons”) will recognize that Montherlant’s novel is homage paid to Laclos by a modern master.

It is an earlier novel, however, “Les célibataires,” which was awarded the Grand Prix de Littérature de l’Académie Française and the English Northcliffe Prize, that qualifies as Montherlant’s unchallengeable masterpiece. (An English edition translated by Terence Kilmartin is still available from Quartet Encounters). It is the story of a debacle. When Madame de Coantré dies in 1924 — ruined — there is literally nothing left to sustain her middleaged son, Count Léon de Coantré, or his uncle, Elie de Coëtquidan, who had shared with them a cloistered existence in the mother’s villa off the Boulevard Arago, in the 14th arrondissement. These nobles — Léon intellectually gifted, and Elie fundamentally stupid — are quite incapable of making their own ways in the world: Each is in his own inimitable way squalid and incurably eccentric. There is a difference between them: Léon is almost devoid of malice, while malice courses through Elie’s veins. The rich man of the family is Baron Octave de Coëtquidan, Léon’s older uncle, a banker in his own way incompetent, but holding a high position through the favor of a lifelong friend. He too had an analogue in Montherlant’s uncle Guy de Courcy, who helped Montherlant into a low level job at the insurance company before he entered the war as an auxiliaire.

The portrait Montherlant paints of Paris and French bourgeoisie in the first three decades of the 20th century is of a brilliance and acuteness that demonstrate the filiation of this novel from Balzac and Maupassant. We see Baron Octave come to the aid of his brother and let his nephew starve — crever — if he must. In fact, Léon dies of what must be a stroke upon learning that his uncle, knowing that Léon has not a penny left, has made a careless and large gift to a charity that he boasted held no interest for him. It is in its own way an acte gratuit. As I have discovered rereading them one after another, Léon’s death and burial hold their own with the agony and burial of le Père Goriot in Balzac’s eponymous novel. But Balzac makes room for some decent sentiment, some charity, some hope. Rastignac and Bianchon ease the old man’s last moments and see him to his grave, even if the daughters abandon him. There is no such relief in the pitiless universe of “Les célibataires.”

Mr. Begley is the author of eight novels, including “Wartime Lies,” “About Schmidt,” and most recently “Matters of Honor.”