I learned programming on the job via high-level languages. I'm trying to gain a better understanding of the lower-level workings of computing and picked up "Design of the UNIX Operating System" by Maurice Bach.

What do I need to know in terms of which topics in this book may not be relevant to understanding Linux nuts and bolts? Is there a newer book or Linux-specific book that I should read instead? I really like the clarity of this particular book, though.