From Elvis Presley's Sun Sessions to Radiohead's OK Computer, here is the very best of rock and pop music of the Twentieth Century. A consumer's critical guide

It defined a generation, exemplified an era: Woodstock was unlike anything that has ever happened before or since--and August 2009 marks the 40th anniversary of

Chris Smith tells the fascinating stories behind the most groundbreaking, influential, and often controversial albums ever recorded.

So much more than another best-ever roundup, here you'll find the reasons why these 100 albums deserve recognition for the way in which they transformed music.