Building Secure Servers is aimed at the practical administrator. Bauer plunges in with recommended DMZ designs. He then covers general Linux hardening principles and practises, before looking at specific applications.

This is what sets the book aside from many other security guides. With this one book, you get a top-to-bottom guide on building a secure Apache web server, DNS and email server.

For me, Bauer gets the balance between theory and practise.

The only downside for me was the lack of information on the increasingly popular security-oriented kernel patches LIDS and grsecurity : a reader may not realise they even exist.