Between the mid 1960s and the late 1970s, the long-playing record and the albums that graced its grooves changed popular music for ever. For the first time, musicians could escape the confines of the three-minute pop single and express themselves as never before across the expanded artistic canvas of the album. The LP allowed popular music become an art form - from the glorious artwork adorning gatefold sleeves, to the ideas and concepts that bound the songs together, to the unforgettable music itself.