I bought the first edition of this book to introduce myself to the world of Linux. It is well structured and quite understandable for someone who is taking his first steps in the Linux O/S. Covers basic theory like file system structure, booting and shutting down to more advanced like routing, performance analysis, etc
If you want to dive more into the linux world you would probably need to buy additional material on specific technologies like mail systems, iptables, etc. It is definitely a good book to start with and a nice complement for any additional linux material. A must have in any administrators’ bookself, I really loved it!