I read Slash's bio and while it was good, I found Duff McKagan's first bio to be my favorite of the GNR bios. That guy really motivated me to get back to school. I mean if the former "King of Beers" and bassist for the "most dangerous band in the world" was able to go college and get a degree, I have no excuse at all in the position I'm in.
I mean this is the guy that almost literally drink himself to death (suffered Pancreatitis in 1994), decided to get himself clean (mainly for his mother), and was not content on just the success he had with GNR and decided to invest in stocks with Microsoft, Amazon, and Starbucks back in 1995, and then decided to go back to higher education and manage to get a degree in finance in Seattle, and is able to have a loving family of his own for 20+ years. To me, that speaks huge volume of what Duff McKagan is as a person than anything he ever done music-wise (which is still big and important, don't get me wrong).