Like a Big Brother
Like an older brother teaching you how to drive stick
The content is one part why this book is great, but I think bigger points go to Robert Love's delivery. His style is casual yet not willy nilly. A subject like the kernel is both dense and minutia-filled and in turn is so much easier to grasp when it's not presented in a dry academic style. This book is a good contrast to McKusick's Design and Implementation of BSD, which is technically/theoretically on point but in all truths _kinda_ boring. The way I would characterize this book -- it's as if you're older brother took you aside and taught you how to hack the mainframe.
The reviewer gave five stars; I hope you do, too.
Sidenote, I am indeed the oldest of two brothers, but I wish I had an older brother. Not to teach me to drive stick, but to score me smack and women.
Also check out Linux in a Nutshell 5ed, an excellent Linux quick reference, up-to-date with the current state of Linux systems.