Revealing all

This alone makes “Degas and the Nude,’’ a new exhibition at the Museum of Fine Arts, one of the most electrifying exhibitions to open in Boston for years. The show opens to MFA members today and to the general public on Sunday.

If you come to the show with an image of Degas as the painter of pretty ballerinas and horse track scenes, be prepared to find something tougher. If, on the other hand, you come with your defenses up - convinced that Degas, along with being an anti-Semite, was also a misogynist - prepare to have these defenses weakened.

The MFA exhibition is the first museum show ever devoted to the subject of Degas’s career-long engagement with the naked human form. Organized by the MFA’s outgoing chairman of the Art of Europe, George Shackelford, along with the Musee d’Orsay’s Xavier Rey, it contains 160 works, more than a third of them lent by the Paris museum (where the show will open in March).

From the 1870s until about 10 years before his death in 1917, Degas knocked out one magnificently drawn, gauchely posed female nude after another. Only the means and the materials changed - charcoal, pastel, paint, monotype, lithograph, clay, pastel on monotype, and so on.

These now look like some of the greatest nudes in the history of Western art. Picking up on cultural currents that were gaining momentum in the mid-19th century, Degas aggressively stripped away centuries of idealization, sentimentality, and pomposity to reveal the female form as it was.

There was, however, an obsessiveness about the endeavor that can be disconcerting. You sense pride in Degas’s refusal to prettify, and relish in the way he continually contrived the most awkward-looking poses for his models. Right from the beginning, people described them as brutal, cruel, animalistic.

But Degas’s almost machine-like detachment is in constant tension with a sustained engagement that is sensual, marveling, and tactile. The effect, aesthetically, is a hot and cold dynamic unlike anything else in art.

Degas was the oldest of five children (three others died in infancy). His mother, worn out by child-bearing, died when he was 13. He was a lifelong bachelor who said he wanted to be “illustrious and unknown.’’

He had, according to biographer Roy McMullen, “an ironic intelligence and veiled morosity.’’ Unlike his friend and rival, Édouard Manet, who adored women (just as they seemed to adore him), Degas’s relationships with women were difficult to characterize.

There were many women to whom he was close, and he painted sympathetic and insightful portraits of them. He was friends, as the art historian Norma Broude has pointed out, with an avowed feminist, the Italian journalist Diego Martelli. And he actively supported and encouraged a number of female artists, not least the American Mary Cassatt.

Against that, there’s the indisputable fact that Degas revealed, particularly toward the end of his career, a vilely anti-Semitic streak - all the more dismaying in light of his intimate, lifelong friendship with the Jewish Halévy family. Bigotry is rarely confined within the human heart: It spreads and devours.

So did he like women? The question has limited relevance to one’s experience before the pictures, at which point Degas’s personality recedes: It’s between you and them. But for what it’s worth, I’m inclined to think that he liked women - and not just their bodies.

Sure, it was complicated. But you don’t spend your life drawing and painting women in situations of extreme intimacy without feeling something richer, deeper, and more sympathetic than the brutality so many commentators have ascribed to Degas.

There are some handsome boys and men near the start of the MFA exhibition. But thereafter, the show is a veritable cascade of naked female flesh. The impact is inevitably erotic. But Degas - despite his patent disinterest in these women’s faces - was no pornographer. He was always hosing down the ardent rushes of intimacy his images provoke - pulling you in, then holding you at arm’s length.

The show kicks off with juvenilia that establish themes, work habits, and even specific poses that recur throughout the show.

We’re offered a taste in the first room of Degas’s early academic studies. Aside from attesting to Degas’s precocious talent, they remind us of the strict, classical training he undertook and of the absolute importance within this tradition of mastering the unclothed human figure.

More than a ghostly vestige of what was drilled into him in these years persists in everything that follows. Even as, later in life, he paints ballet dancers or maids serving hot chocolate to their mistresses, he must first render them naked, so as to get the anatomy, the weight, the lines just so.

The two key early pictures are “Young Spartans Exercising,’’ which he first painted in 1860-62, substantially reworking it 20 years later, and “Scene of War in the Middle Ages,’’ from 1863-65. Both were history paintings intended for the prestigious but increasingly out-of-touch Salon. They were painted before Degas turned to contemporary subject matter.

Both pictures are endlessly fascinating, but essentially duds. They’re the product of a young man’s overheated imagination. Their very earnestness invites ridicule.

What makes them so important in the context of this show is that each contains nine naked figures - mostly standing in “Young Spartans,’’ and fleeing or splayed on the ground in “Scene of War,’’ which is an unblinking yet weirdly stilted depiction of wartime rape.

Individual studies for these figures hang beside the finished pictures. They’re beautiful, and in some cases almost painfully erotic. But the worked-up paintings never shake off the sense that they’re awkward composites of all the studies.

Still, their importance to Degas becomes evident as one proceeds through the show. Again and again, the poses and gestures depicted so fastidiously in those two paintings reappear in depictions of women bathing, drying, or brushing their hair.

How much are we liking Degas so far?

You might want to suspend judgment until after the next room, which is devoted to his notorious brothel pictures. These works, which inspired the aging but still concupiscent Picasso 80 years later, are small monotypes - ink applied to a metal plate then pressed to paper.

Monotypes allowed Degas to play freely - often using his fingers or a rag - with light and shadow, either by covering the plate in black ink then creating highlights by wiping it off, or by starting with an empty plate and drawing onto it in black with his fingers.

The effects he achieved - in their economy, their expressiveness, their smudged and shadowy atmospheres - are utterly brilliant. But they hardly distract us from what Degas shows, which is (for the most part) unattractive, semi-naked women with visible pubic hair (shocking - and a clear indicator of depravity - at the time) displaying themselves before clients, washing themselves, preparing to take clients to bed, masturbating, or engaged in lesbian sex.

There’s a Rabelaisian humor in the brothel monotypes, which Degas seems to have made from memory and in a caricaturing spirit. And they’re refreshingly frank about some of the realities of prostitution.

But there’s also, I find, a note of revulsion - Degas contriving and exaggerating ugliness rather than merely reporting on it.

The note of revulsion evaporates in the pictures of women at their toilette that make up the bulk of the rest of the show. These pastels, drawings, sculptures, and paintings are ravishing, and there’s room after jaw-dropping room of them. Full of movement and expression, they harmonize beauty and truth, seeming tethered to a specific moment, but also weirdly out of time, insulated from the roar of history - as true intimacy is.

In all these works, you feel Degas’s intellectual and emotional blinkers in excruciating tension with his voluptuous, caressing line, his frenzied, layered cross-hatching in acidic greens, pinks, blues, oranges, and turquoise - colors that become stronger and stranger as the old man’s eyes get feebler.

There are individual masterpieces aplenty. But there is also an extraordinary cumulative effect. Never have you seen so many - and such beautiful - spines swerving and bending into buttocks, catching the light or receding into colored shadow.

Walking through these rooms, you feel Degas determinedly dismantling the conventions of the idealized nude, as only someone who knew and loved those conventions could. He wanted to show women in awkward, off-kilter, but always believable poses, and from ever-shifting vantage points - from the next room, from close up, from behind, from in front, from virtually on top of.

In each room, Shackelford and Rey have peppered Degas’s works with a number of pictures by other artists, from his heroes Ingres and Delacroix to (among others) Cassatt, Caillebotte (the marvelous new MFA acquisition, “Man at His Bath’’), Picasso, Bonnard, and Matisse. But for me, the most telling juxtaposition was between Renoir’s “Woman Combing Her Hair,’’ from 1882-83, and Degas’s “Woman Brushing Her Hair,’’ made a year earlier.

The Renoir is gorgeous, but it’s soft porn: The seated woman is seen from behind against a pearly, inchoate background, one plump breast suspended ripely between arm and torso. Renoir captures the light reflecting off her wet, matted, red hair with brilliant aplomb.

In his own, slightly larger canvas, also in oil, Degas achieves similar though less-twinkling light effects in his own model’s wet red hair. But her hair seems straggly and knotted, so that where the brushing gesture of Renoir’s model is all fluid grace, the comb of Degas’s model is stuck in a clump.

She’s overweight, her skin has an unhealthy pallor, and she’s seen from above, as if the artist were hanging from a chandelier. The result is a portrayal that’s awkward and unsettling in a way that Renoir would never allow.

In their obliviousness, Degas’s bathers can seem inviolate, charged with a physical dignity that at times approaches the sacred. It’s the dignity of humans going about their private business unobserved, honoring the animal in themselves. In these images, you feel the artist channeling the poignant dignity of the Biblical Susannah, or of the goddess Diana and her nymphs before their discovery by Actaeon.

But at other times, Degas - conscious, perhaps, of himself as a modern Actaeon, breaking in on scenes never intended for him - seems interested in the threat or aftermath of violation. It’s this ambivalence, perhaps, that produces the edge, the poison, in his art.

Sebastian Smee can be reached at ssmee@globe.com.