Diane Arbus was American photography’s bravest detective. Born in 1923 and raised in leafy privilege (her father was the president of a department store on Fifth Avenue), the young Arbus spurned the path of bourgeois domesticity and propriety to patrol the outskirts and no-go areas of the demimonde, armed with only a 35-mm. Nikon and a fierce supply of inquisitive nerve. She haunted flea circuses, carnival sideshows, and strip clubs, made nighttime expeditions into Times Square and Coney Island (then at their most dangerous and squalid), and recorded life on the fly on New York City streets.

Like so many photographers in the heyday of Henri Cartier-Bresson, Arbus was in pursuit of the “decisive moment,” the chance epiphany. It was when she upgraded from the Nikon to the medium-format Rolleiflex, with its bulkier body, larger negative, and square frame, that she found her true eye, her visual voice. The roving voyeurism of 35-mm. street photography had prepared the stage for a formal portraiture where Arbus and her subjects faced each other full-on for posterity.

What was revelatory at the time and remains controversial to this day was that Arbus’s subjects were people who had been marginalized, stigmatized, and ostracized by polite society and mainstream culture: giants, dwarfs, circus freaks, homes for the developmentally disabled, nudists, female impersonators with false eyelashes out to here. Critics, most prominently Susan Sontag, would accuse Arbus of exploiting a peep-show mentality and trafficking in grotesquerie, but such ethical objections failed to reckon with the classical poise and becalmed clarity of the images, their eerie hold on the viewer. That’s why they’ve endured and entered the lexicon of pop-culture lore—the twins in Stanley Kubrick’s The Shining, a virtual quotation of Arbus’s Identical Twins, Roselle, N.J. (1967), are but one example. As Arbus herself wrote of her subjects, “The stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you.” —James Wolcott