WHILE THE CURSE OF FAME is to be undressed in public, it comes with the song of a Siren. Fame seduces its victims into participating in the disrobing. Vanity feeds on display, and there is almost never enough.

So it often seems with Simone de Beauvoir and Jean-Paul Sartre--students, lovers, writers and rebels together for almost 50 years. We learn a great deal more about this most famous of literary-intellectual couples in Adieux and After the Second Sex. Not all of it is worth knowing. Some of it is worth not knowing. And all of it comes in their own words, making them their own victims.

De Beauvoir's farewell to Sartre consists of a journal of the last 10 years of their life together, closing with Sartre's death on April 15, 1980, at the age of 75, and a long interview with Sartre in Rome and Paris during the summer and fall of 1974 as Sartre's health went up and down, and as de Beauvoir recorded the final thoughts of the man she idolized.

Books like Adieux surely come from what we call love. But this emotion is blind, and the Sartre we see here can't be the one de Beauvoir had in mind commemorating. He frequently acts and sounds like a doddering village preacher rather than one of the powerhouses of 20th-century existentialist thought.

Although his career is at twilight, Sartre sees the publication of three volumes of his incomplete study of Flaubert, The Family Idiot. He and de Beauvoir unsuccessfully try to launch a French television series summarizing the 20th century. As an aged cog of institutionalized French radicalism, Sartre slowly moves from rampart to rampart, giving speeches, signing manifestoes, or making public appearances in support of some two dozen lost leftist causes, including the imprisonment of Andreas Baader by German authorities.

But he is ill and growing gravely ill. Strokes, diabetes, abscessed teeth are followed by arteritis, uremia, and almost complete blindness. He loses control of his bladder and bowels, and his mind occasionally unravels. He reports on imaginary visitors, sees his cigarettes burning up in the gutter, and appears "rather sleepy, almost glum, with a fixed smile of universal kindness on his lips (a smile caused by a slight paralysis of the facial muscles.)"

On the bad days, Sartre thinks his time is up: "I can't work anymore . . . I'm gaga, as they say." Or, "I'm not stupid. But I'm empty." But on the good days he looks for another 20 years or figures he has at least until the age of 81.

Sartre's prevailing attitude--when he was fully aware of his surroundings--was a quiet acceptance of his fate. He was no longer the existentialist assessing contingencies and inventing himself.

"All right," he says to the movie producer Contat, "I've done what I had to do.... I've written, I've lived; there's nothing to regret. . . . I don't have the feeling of old age."

But his mental state is also one of denial, confusion, and contradiction. While he says that "there are not many things left that excite me" and that "I set myself on a rather higher plane," the behavior reported by de Beauvoir suggests otherwise.

Sartre frequently drank until he collapsed. He was probably an alcoholic and at least a lush. Although he was surrounded by women--his beloved "Beaver" (de Beauvoir), Arlette, Wanda, Alice, Sylvie, Liliane, Michele, Melina, most of whom took turns spending nights with him --he continually collected girls. And not just for afternoons and nights. He enlisted them in his alcoholic struggles with de Beauvoir, and they helped him hide vodka behind his books. Once his prized lover, de Beauvoir found herself policing his sexual romps in order to keep him sober and thus alive.

We're told that a crowd of 50,000 followed the hearse to Montparnasse cemetery the day of Sartre's funeral. But none could equal the devotion to Sartre that de Beauvoir displays in Adieux. There was no service, no kindness, no humiliation she refused on his behalf, and a wrenching scene the night he died shows her uncensored depth of feeling for him:

"At one point I asked to be left alone with Sartre, and I made as if to lie down beside him under the sheet. A nurse stopped me. 'No. Take care . . . the gangrene.' It was then that I understood the real nature of the bedsores. I lay on top of the sheet and I slept a little."

The conversations between de Beauvoir and Sartre that make up the last two-thirds of Adieux and the interviews between Alice Schwarzer and Sartre and de Beauvoir in After the Second Sex took place in part as Sartre and his feminine traveling companions--they included Schwarzer--were seeking sun and rest in Rome in 1974. Sartre spent more time traveling--to Provence, Italy, Greece--in his last several years than doing anything else. De Beauvoir read to him. They ate well. He walked a little. They talked a lot. He found a few new women.

One leaves the de Beauvoir-Sartre exchanges of 1974 informed, occasionally moved, and often unenthusiastic about Sartrean existentialism. The dialogue deals mostly with the personal, the intimate, the hegemonic in Sartre's childhood, career, and life with de Beauvoir.

Generally she serves him questions like a doting mother rather than a rigorous interrogator, and it's a bizarre spectacle to see the great feminist behaving like a feminine stereotype.

Sartre talks, for example, about a love affair with "the Moon Woman" and says, "I think my machismo lay more in a certain way of looking upon the world of women as something inferior, but not the women I actually knew."

De Beauvoir replies: "Your Pygmalion side shows that you've never wanted to reduce, keep, or hold a woman to a state that seemed to you inferior on any plane at all."

Sartre replies: "No."

That's not enough. De Beauvoir responds: "On the contrary, you've always wanted to bring them on, to make them read and discuss things."

But by his own admission Sartre never lived in "the real world" with any of his lovers. His bond with de Beauvoir "caused the inferiority of those relations." The fact is he used women. We hear nothing about their discussing things here. We hear about Sartre's "embracing, caressing, and kissing (bodies) all over." His responses are in terms of masturbation, intercourse, the logic of sexual intimacy in relationships, not the power of intellectual vibrations.

Late 20th-century philosophic thought seems to have moved beyond Sartrean existentialism, and the reasons are implicit in Adieux and After the Second Sex.

We learn that Sartre, who says he considered himself a genius, wrote much of his Critique of Dialectical Reason and other philosophical works on amphetamines (10 in the morning) and sleeping pills (five at night) to achieve a state of "completely bodily surrender" and to feel self-perception "through the movement of my pen." We also learn that in Sartre's system of values "the hierarchy is philosophy second and literature first" and that "philosophy... gave me the dimensions necessary for creating a tale." His ideas were for fiction.

It's also unsettling to hear from Sartre that at the height of post-World War II tensions between the United States and the Soviet Union he believed that France would be invaded again. And what was the philosopher thinking about? How to avoid a war? No. He was thinking about whether in the event of war he should flee France.

Emphasizing individualism, existentialism has produced extraordinary effects. De Beauvoir's feminist movement, still only touching "a very small number of women," can be traced to her existentialist proposition that "one is not born, but rather becomes, a woman." Focusing on the self, existentialism forced the individual to confront his or her own actions as the means by which social change would take place, and much of Sartre's and de Beauvoir's political lives and literary works demonstrated their belief in this proposition. Communism and Maoism in their conversations are social forces, not merely ideologies.

But existentialism seems to have lost momentum, and some philosophers believe that their discipline has moved beyond it. One reason is that many existentialists, like Sartre, have often been something else--novelists, playwrights, composers, theologians. Another reason is that existentialism, as de Beauvoir and Sartre show us in their conversations, has been concerned excessively with the theatrical, the dramatic, and the romantic. As a way of thinking about one's life, existentialism may still seem attractive. As a way of thinking about the world, it may seem too limited. It has this quality in common with Freudian psychoanalysis.

One ruminates along these lines upon closing Adieux and After the Second Sex because so much here is extremely private, sadly moving; but while demonstrating certain existential convictions, the books also underscore the personalism of a philosophy that has made claims of universality.

We should remember it was Sartre in No Exit who told us that "hell is other people," that Sartre's fundamental insights came from intuition and that he was proud of being poor at science, mathematics, and economics. To Simone de Beauvoir, Sartre appears to have been possessed by Truth. To most who meet him here, he and his philosophy will seem possessed by circumstance.