The Bonham book is written by Chris Welch of Melody Maker fame and drummer Jeff Nichols called A Thunder of Drums-it's mostly a coffee table book with lots of photos and the stuff on Bonham in his pre-Zeppelin days is typical fodder fare but a couple of tidbits did peak my attention; Nichols argues persuasively that much of Bohnam's sound wasn't made from him using redwood trees with which to bash the drums but it was in where he didn't play, those pauses between a pattern that show his gift as a creative drummer. Secondly, his increased self-destruction from alcohol was much to do with his growing resentment at not being credited for his musical contribution on recordings e.g., he cam up with the droning guitar progression on Kashmir.
The Bruford book is an autobiography with forwards written by Mark Guiliana and Mike Portnoy. It is a treasure with wit and brilliant analyses of the state of the music business then and now and the bumps and bruises sustained moving from the rock world to the jazz world. It's right over 300 pages but well worth the effort.