Mr. Ligon in the early ’90s undertook a project, “Notes on the Margin of the Black Book,” that collected texts, including his own, commenting on the issues raised by the Mapplethorpe photographs. Remounted at the Guggenheim, his installation touches on the unease felt by gay black men when they view bodies they find attractive in what they also consider to be dehumanizing depictions by a white observer.

He cites an essay by the black film director and artist Isaac Julien and Kobena Mercer, now a professor of art history and African-American studies at Yale: “Mapplethorpe appropriates the conventions of porn’s racialized codes of representation, and by abstracting its stereotypes into ‘art,’ he makes racism’s phantasms of desire respectable.” (Mr. Mercer later expressed more ambivalence, in part because of the ways that black gay artists, like Mr. Julien and Mr. Fani-Kayode, have made use of Mapplethorpe’s work.)

In one of the texts that Mr. Ligon includes, the novelist Alan Hollinghurst writes that Mapplethorpe was not “unaware of the political implications of a white man shooting physically magnificent black men, and such implicit tensions lend a piquancy to these pictures.” But “piquancy” seems the wrong word to describe a work like “Thomas,” from 1987, a vertical diptych with a favorite model that combines a photograph of a classically posed naked black man with an egregious swatch of leopard-skin fabric . I don’t believe Mapplethorpe was being ironic here. The grandiosity of his ambition (he compared himself to Michelangelo) rarely allowed for humor.

But there is one notable image that arouses humor and uneasiness with a punch that still stuns. Arguably his best picture, as well as the most notorious, “Man in Polyester Suit” depicts a large penis that flops out of the fly of a cheap business suit. Impeccably staged, the photograph excludes the model’s head (Milton Moore didn’t want to be identifiable). The cropped format might have been a department-store suit ad, except that here it is instilling desire for the body part and not the garment. Indeed, the condescension toward the suit — and, by implication, the man who has selected it — contributes greatly to the disturbing sense that this faceless man has just one thing to offer. “It is supposed to be shocking,” wrote the critic Arthur Danto.