kyle s edited the summary of Pearl Jam Twenty Thursday, December 29, 2011.
A year by year description of everything that happened to the band as a band. It is not a tell all in that it does not really talk about the members personal lives or go into great detail about when drummers left the band. It did talk extensively about how the band was formed, albums were created, certain relationships (Neil Young, Soundgarden, Nirvana, Chili Peppers, The Who, etc., and milestones in their career.
You can tell the author is a fan. Focuses a lot on the early years (which is great) including the origins from the ashes of Mother Love Bone (due to death). It also details the creative process for each album. It also demonstrates the high points and some low points in the band's history.