The first country music hit is often traced to Vernon Dalhart’s “Wreck Of The Old 97” from 1924. The first country music hit by a female artist wouldn’t come about until three decades later, in 1952.

The 1960s were a boom time for country music. Sometimes that just happens in a genre—there are fat times, and there are lean times. And in the 1960s, country music was in an especially productive ...