I've spent the past few months reading about the early days of rock 'n' roll; Elvis (Last Train to Memphis, Peter Gurarlnick), Little Richard (The Life and Times of Little Richard, Charles White) and the birth of Soul music (Sweet Soul Music, Guralnick).
In Footsteps in the Dark, George Lipsitz, discusses the "long fetch of history" - how a very small event that seemingly will go unnoticed can have a profound impact.
It has been fascinating reading about people, mostly men (except for Estelle Axton, from Stax Records), who helped to create and shape the regional music scenes in the South in the late 1950's that later helped to (re)define popular music in America.
It seems to me that the 1950's, especially the latter half, were far more revolutionary for popular (rock) music than the musical events of the 1960's. The pioneers of that era, the musicians, songwriters, label owners and many others, created the pathways for the next wave (the Beatles, Bob Dylan, etc...) to walk on.
It is always easier to pass through the doorway, once it's been opened for you.