While most bands undergo a number of changes over the course of their careers, few of them experienced more radical stylistic evolution than Fleetwood Mac. Initially conceived as a hard-edged British blues combo in the late '60s, the band gradually evolved into a polished pop/rock act over the course of a decade. Throughout all of their incarnations, the only consistent members of Fleetwood Mac were drummer Mick Fleetwood and bassist John McVie -- the rhythm section that provided the band with their name.