When Egon Schiele died on All Hallows’ Eve in 1918, a victim of the Spanish influenza pandemic that killed 40 million people–including his pregnant wife, who had died three days before him–he was 28. Schiele had been poised to assume the position of Vienna’s leading artist, having abruptly arrived at his signature style in 1910, at the age of 20. The change was more like a metamorphosis than a transformation. Schiele had been a precocious student, but nothing he did before 1910 would have prepared anyone for the singular artist he all at once became. The only parallel case that comes to mind is that of Arthur Rimbaud, writing urgent and unprecedented verse while still a schoolboy. Rimbaud and Schiele were comparable geniuses, and Schiele was in a way a vilain bonhomme, as Rimbaud and his drinking buddies called themselves. But Schiele’s rebelliousness was part of the overall secessionist spirit that possessed twentieth-century artists impatient for official academic art to be junked and Modernism to begin.

There was nothing criminal in his character, as there had been with Rimbaud, but the extreme eroticism that marked his work–and his use of very young models–raised suspicions that he was capable of transgressive sexual acts. Indeed, he was jailed in 1912, accused of abducting and sexually abusing an underage female, while he was living in a small village outside Vienna with his long-term lover and model, Wally. At the trial the charges were refuted, but one can easily understand, on the evidence of his art, how he could be believed capable of sexual delinquency. The authorities found pinned to his studio wall an evidently salacious drawing of a young woman, naked from the waist down. He was sentenced to an extra three days in prison–his incarceration lasted twenty-four days in all–on the ground that he displayed an indecent picture where it could be seen by innocent eyes. The offending image was subjected to judicial destruction. Interestingly, the fact that the authorities found drawers full of similarly “indecent” images did not count against him. The offense was showing, not making, dirty pictures.

Eroticism and pictorial representation have coexisted since the beginning of art, and many great artists have a few erotic images in their “X Portfolios” (to use Robert Mapplethorpe’s term). But Schiele was unique in making eroticism the defining motif of his impressive if circumscribed oeuvre. He was also unique in that drawing was his chief medium. Willem de Kooning said that flesh was the reason oil painting was invented, but Schiele demonstrated how remarkably fleshly thin transparent washes of pale color can be. Consider the iconic self-portrait of 1910, in which the naked artist is gazing–or glowering–at himself in a mirror, over his left shoulder. The right arm is bent around his head, which he grasps with his hand. The fingers are abnormally long, and his face is focused in a look of intense concentration: One eyebrow is raised, the mouth is pursed in a sullen grimace. The left arm, all bone and stringy muscles, falls straight down from shoulder to a flared elbow. Whatever he is looking for in the mirror, the artist is as confident as the drawing of his arm, his outthrust rib cage, his curved back, his narrow waist. Lines of tension give definition to his body, matching the ferocity of his look. Two features call for specific comment: the wiry thatch of hair beneath his right arm–echoed by a curl of pubic hair at the bottom of the sheet–and his right nipple, red almost to the point of blackness. These express not so much the gender as the sexuality of the body. The hair is not indicated but drawn, and the nipple suggests a target. There is a touch of red on the elbow so sure in its execution as to take one’s breath away. The same red is on the cheekbones and on the finger clasped around the artist’s head. There is nothing else in the self-portrait besides Schiele and the signature initial S in the lower right corner. The paper is yellowish. The figure is cropped, which heightens the intensity both of the posture and the execution. The accuracy of the drawing is confirmed by several photographs, in which Schiele contemplates himself in the mirror, clearly proud of his looks, his elegant figure, his leonine head of hair. Unquestionably, this is a vain young man.

Schiele was 20 when he drew his self-portrait. Compare it with any of the earlier drawings of nudes in the exhibition of Schiele’s art on view at the Neue Galerie in New York City through February 20, and you will see instantly what I mean by the abruptness of his style. All of a sudden, and until the end of his pathetically brief career, everything is mobilized to express the sexuality of the human body. Schiele inevitably drew many naked figures in the course of his academic education. The sexual attributes are all shown. But in his final style, the whole body expresses its sexuality. If I can put it somewhat paradoxically, he has found a style that sexualizes eroticism. In Schiele’s work the human body expresses its sexuality as artistic truth.

In art history textbooks, Schiele is often and carelessly labeled an Expressionist, a description intended to distinguish his eroticism from the decorative eroticism of his mentor, Gustav Klimt. Klimt, of course, depicted lovers clasped to each other in intense erotic embrace. There is nevertheless something operatic about Klimt’s lovers, as if they were figures in a myth. Like Tristan and Isolde they are caught up in the sweep of passion as the music swells around them. Sex is somehow meant to be transfigurative, a way of transcending the sweaty realities of the flesh depicted. Schiele’s figures, by contrast, are raw, hairy and bony, their young bodies marked by erotic zones like maps of where to touch each other. Sex is what they live for, the essence of their lives. It is an end in itself, not a means for transfiguration. They can’t keep their hands to themselves when they are together, and they can’t keep their hands off themselves when they are alone. Masturbation is their default state.

In their leanness, Schiele’s figures might be said to resemble those of Picasso’s Blue Period. But Picasso’s figures are gaunt because they are poor and needy, whereas Schiele’s have no thought for eating, as their only hunger is for sex. They are like illustrations of a thesis of Sigmund Freud, Schiele’s fellow Viennese, that human reality is essentially sexual. What I mean to say is that there is no art-historical explanation of Schiele’s vision. Expressionism was certainly in the air in Mitteleuropa in those years. But his drawings look like nothing one would see by artists who belong to movements like Die Brücke (“The Bridge”) or Der Blaue Reiter (“The Blue Rider”). The German Expressionists used heavy black outlines and were inspired by a vision of primitivism. My own view, hardly inspired, is that Schiele expressed what Freud describes in his central thesis about human nature and conduct–that from infancy on, sex relentlessly holds us in its grip. In Schiele’s work we see what we know is repressed in the men and women painted by Edvard Munch, the artist I think Schiele is closest to in terms of achievement.

The reference to Freud is not an appeal to a Viennese zeitgeist by which Schiele’s work might be unpacked, although I think it says something about Vienna before World War I that eroticism was the main artistic achievement of the Austrian capital’s most original artist at the time. Rather, I mean to suggest that Schiele is likely to have known about Freud’s views, whose Three Contributions to the Theory of Sex was published in 1905. Consider Schiele’s extraordinary Mother and Child, another drawing from 1910. The theme of mother and child has a considerable history in Western art, from Venus and Eros to the Madonna and the Christ Child, but there is nothing to compare with Schiele’s study. The mother is shown from behind, looking over her shoulder, gazing back with a flirtatious glance. Her body is curved in a particularly sexy way, giving a thrust to her hips and a saucy swing to her generous buttocks. She is nude except for her black stockings, and we can see the tip of one breast from the side. The child is sitting next to her, on the arm of the chair the mother leans into. One of his hands is pressed against her waist, which he appears to be kissing with the intense fervor with which he would be sucking at the breast, if that were anatomically possible. The other hand conveys the child’s total absorption in the mother’s flesh. It is very much as if they are lovers–hardly a posture that would have occurred to anyone had the idea of infantile sexuality not been in the air. Schiele had drawn pregnant females at a clinic with a certain obstetrical precision. But Mother and Child has a moral daring, and it expresses a psychological truth. Interestingly, the pair is surrounded by a kind of white aura, scrubbed onto the yellow of the paper, and the flesh itself is given life by the way the paint is swirled on, as in finger painting. The space where the buttocks join the thighs is punctuated by a dark cross as black as the mother’s eye or hair.

Kneeling Semi-Nude, done in 1917, shows how little Schiele’s style and vision had evolved over seven years. The naked upper body of the kneeling woman emerges from a voluminous frilled undergarment. She is intensely involved in palpating her left breast, holding it in her right hand while she probes above the nipple with the other hand. The round red nipple is fully exposed, and the woman is peering at it with such intensity that the celebrated male gaze of contemporary feminist theory appears by contrast to be a passing glance. Like all of Schiele’s women, she is slender and beautiful, and her face is framed marvelously by tangled black curls. Lips, cheek and nipple are the only touches of red in the otherwise neutrally painted body.

With their audacious use of female underwear, boots and dark stockings, Schiele’s drawings express erotic fantasies that would not have been out of place in underground postcards of the era. They are transcriptions of how Schiele and his patrons imagined sex, and they belong to the edge between pornography and art that Mapplethorpe would also explore. The images of men and women masturbating, or making love–and especially the pictures of lesbian couples–suggest to me that there was a demand for such representations, just as there was a demand for fleshy, dissolute boys in Caravaggio’s Rome. That too tells us something about Schiele’s Vienna, and about those who collected his work and showed it to others–and something perhaps about Freud’s patients, if one insists upon a Viennese zeitgeist. What Schiele’s provocations imply in terms of his own life, on the other hand, remains a mystery.

Schiele made more self-portraits than Rembrandt, and a great many pictures and portraits in the exhibition at the Neue Galerie are not overtly sexual. But the erotic work inflects everything else, as if everyone depicted ne pensent qu’à ça–“thinks only about that”–as the French like to say. The Neue Galerie show is, in essence, an intimate one, almost a family album, with photographs, juvenilia and toys from the artist’s cabinets, and there is enough of the work that made Schiele a great artist to make us feel as if we have gotten to know him and the world to which he and his subjects belonged. Still, the title of the show, “Egon Schiele: The Ronald S. Lauder and Serge Sabarsky Collections,” makes clear that it is a double celebration. Lauder and Sabarsky founded the museum as a venue for German and Austrian art of the early twentieth century, and both were devoted to Schiele at a time when his work was widely scorned. Because it is partly about two collections, and in a way about Schiele’s American reception, the show has limits that one devoted solely to the artist, borrowing from various collections here and abroad, would not have had.

There is, for example, only one of the drawings made by Schiele when he was in jail, awaiting trial and uncertain of his fate. It shows him with a beard and shaven head, leaning back on his prison pallet, wrapped in a reddish greatcoat to keep himself warm. It has the title, probably added later, I love Antitheses (1912). He is suffused with self-pity, and we know from his writing that he was profoundly demoralized by his prison experience. Schiele’s prison images have the quality of Japanese drawings–single skinny unwavering lines define the cell doors and the prison corridor, with brooms, mops and washtubs piled in a corner and spindly branches visible through a window. This is, after all, not Sing Sing but rather a poky provincial jailhouse in Austria. If I were curating a Schiele blockbuster, I would show all the prison drawings I could lay my hands on. And I would display Schiele’s extraordinary painting of his bedroom in Neulengbach, the town where he was arrested, a place almost as monastic as Vincent’s bedroom in Arles. Instead of these arresting images of confinement, the Neue Galerie exhibition gives us Schiele’s landscapes, which to my mind seem too opaque, lacking the transparency of his best work, his scenes of the body in its fleshly joys and torments.

It was, after all, the reinvention of men and women as sexual beings that accounts for Schiele’s greatness. As Sabarsky said, “At last, Schiele is becoming contemporary,” by which he meant that in terms of the representation of sexuality, the times have caught up with and almost overtaken him. Mapplethorpe is in the museums, even if our government keeps its distance from him, and frontal nudity has become commonplace on gallery walls. Yet there is no body of work anywhere that shows the sexuality of human flesh as truthfully as Schiele’s, with the vulnerability and burden of our appetites and imaginations drawn so clearly and with such passion. Freud writes in Civilization and Its Discontents that “the genitals themselves, the sight of which is always exciting, are hardly ever regarded as beautiful.” It is the excitement of the erogenous zones in otherwise beautiful people that makes Schiele’s work so true.