Nimrod Workman was 77 years old when he first entered the recording studio. More than 50 years later, the young producer who helped capture the tracks remembers his friend’s unparalleled impact.

After the release of John Lennon and Yoko Ono‘s 1968 debut album together, Unfinished Music No. 1: Two Virgins, a then-19-year-old actress, Sissy Spacek, performing under the pseudonym Rainbo, ...