By 1978, three years into his tenure at Saturday Night Live, John Belushi, 29, was obsessed with the trappings of rhythm and blues. He bought a dark-brown fedora, black Ray-Bans, and a dark suit coat. His pockets bulged with R&B cassette tapes. He would storm into the home of Bob Tischler, the National Lampoon Radio Hour producer, pull blues albums from his shelves, and play one song from each, leaving them in a teetering stack on the floor. At home, he would serenade guests with a frenetic barrage of 45s.

“What he was doing,” Judy Belushi, John’s wife, says, “was finding out which songs people responded to,” building a Blues Brothers setlist in his head.