The Blues Brothers: An Epic Friendship, the Rise of Improv, and the Making of an American Film Classic

“They're not going to catch us,” Dan Aykroyd, as Elwood Blues, tells his brother Jake, played by John Belushi. “We're on a mission from God.” So opens the musical action comedy The Blues Brothers, which hit theaters on June 20, 1980. Their scripted mission was to save a local Chicago orphanage. But Aykroyd, who conceived and wrote much of the film, had a greater mission: to honor the then-seemingly forgotten tradition of rhythm and blues, some of whose greatest artists-Aretha Franklin, Jame...