Even so, having grown up amid the intolerance of the South, he learned to avoid certain topics at home. One of them was his homosexuality. “I doubt Mother knew that it existed in the world,” Ms. Begneaud said. “I guarantee she had no idea.”

His parents were Christian fundamentalists who went to church two times every Sunday. Rauschenberg had ample opportunity to hear about the torments of hell, which piqued his imagination. In 1958, in an application for a Guggenheim grant, he proposed that he illustrate Dante’s “Inferno” in 34 drawings, one for each canto.

He was passed over for the grant, but he did complete the series of drawings, as the MoMA show will attest. They’re among his best works, combining freely sketched passages with images from newspapers and magazines; they translate a 14th-century epic into a language of his own devising. The “Inferno” drawings represent, among other things, a triumph over Rauschenberg’s dyslexia, signaling his love of literature. “I had a book of Botticelli’s wonderful illustrations of the ‘Inferno,’” Mr. Johns noted recently, referring to the years when he lived a flight below Rauschenberg in a loft building on Front Street. “I believe that Bob’s looking at that triggered his own.”

The Early Blueprints

Does Dante count as one of Rauschenberg’s collaborators? Probably more than Charles Atlas, a video artist prized for his work with choreographers. Now 68, Mr. Atlas is still lanky and boyish, with sideburns that are dyed psychedelic orange. “Someone had the good idea to hire me,” he said with a chuckle when we met recently at MoMA. “It’s the first time they have hired an artist to do anything like this.” Mr. Atlas is designing the video portion of the show, including a nine-channel installation to commemorate “9 Evenings,” a series of quixotic performances that Rauschenberg spearheaded in 1966 with his engineer-friend Billy Kluver, in the hope of forming a brave new alliance between art and technology.

“Bob was so out there,” recalled Susan Weil, a native Manhattanite who met him in Paris as an art student at the Académie Julian in the summer after she finished high school. He was 22 and studying on the G.I. Bill. In the fall, he followed her to Black Mountain College. They married in 1950 and moved to West 95th Street, into a cramped studio apartment. The MoMA show will open with their collaborations — namely, the so-called “blueprints,” life-size photograms in which their bodies appear as white silhouettes bathed against a Prussian blue background.