One of the numerous reasons why the most creative half dozen years or so in popular music was from 1967 to 1973 involved the advent of what has become known as “concept albums”; i.e., records that were put together with an overall (if somewhat-loose) “theme.”

Such classic examples include the Vanilla Fudge’s The Beat Goes On (history lessons, musical and otherwise), the Who’s Tommy (a “rock opera,” which is a concept itself, and also evolved during the same time period), the Moody Blues’ Days of Future Passed (a day in the life on an individual, morning to night).