The Mamas & The Papas enjoyed an incredible stretch of success in the 60s, proving that the vocal group approach still had legs in the psychedelic rock era. But theirs was a relatively brief heyday.

Writing a hit record is like catching lightning in a bottle, and sometimes, you don’t know that you caught it until after the fact. Such was the case for The Mamas & The Papas in 1966, who spent hours ...