It’s no surprise that Martin Luther King Jr. was fond of “We Shall Overcome,” but who knew he also liked Bessie Smith? Timothy English unearths such tuneful surprises in Popology, which tries to assess the musical tastes of four major figures from the ’60s: King, John F. Kennedy, Robert F. Kennedy and Thomas Merton. Sure, JFK liked “Camelot,” but Kurt Weill’s melancholy “September Song” was also a favorite. Merton no doubt enjoyed Gregorian chant, but here’s a shocker: He dug the 13th Floor Elevators. RFK was actually compared to The Beatles in contemporary media coverage, and he tried to make the scene by hiring unknown young bands to play parties and benefits. One of them included future star Billy Joel.