I often recommend the book The Design and Implementation of the FreeBSD Operating System by Kirk McKusick and George V. Neville-Neil as the best way to learn about Unix. It teaches all the parts of the Unix kernel (process tables, file systems, network stacks, etc) and the algorithms used. A sysadmin gains keen insights into what is going on, which helps them design new systems and debug running systems. It is an excellent textbook and teaches OS theory and concepts along with the narrative of how FreeBSD works.
However because it has "FreeBSD" in the title, people often ask if there is a Linux version. The truth is that 99% of the book overlaps with Linux's way of doing things.
Is there a real equivalent book for Linux? I asked recently on HN. The answer I got was Linux Kernel Development by Robert Love but I have not yet read it. From reading the Table of Contents it seems to be less textbook, more for the practitioner; less OS theory, more directly for developers. (This is not a criticism... that's exactly what the title would lead one to expect)
Has anyone that has read both give a comparison?