Operating Systems: Three Easy Pieces
This is a really really good book on Operating Systems. Before this I had read (<a href="http://codex.cs.yale.edu/avi/os-book/OS9/slide-dir/index.html" rel="nofollow">http://codex.cs.yale.edu/avi/os-book/OS9/slide-dir/index.htm...</a>), which is itself a really good book, but this one seemed more funnier and less dry, and I think reading two OS books gives you a little different perspective from each.