This really filled the void between the amazing hands-on "Lions Book" and Maurice Bach's "The Design of the UNIX Operating System", introducing the reader to some more modern implementation of the UNIX operating system.
There is some bad in the good though, the text varies in quality, not having code anywhere in the book is sometimes a big miss, you can get pretty exhausted reading this, I meant to get this book as bed time reading, it ended up being more of a reference, with only a few chapters being useful, if you're curious about the internals of the actual system get it, but if you need some more theoretical grasp or a "toy problem" book to truly understand the basics, then get Lions book.
Conclusion, I dont regret having it on my shelf, maybe it just could have been better.

Enjoy.