Rating: 

In the first part, the methodology and tool used are listed and covered. Then the author explains how to investigate the network via querying DNS and scanning the edges of the networks. Specific areas are looked at as well such as web services, remote login and remote desktops, email servers, vpn connections, open ports and open services running as daemons.

For the mindset as much as the practical advice, this is a great book for the toolbox.