When you combine Laura's book with Fyodor's (the guy responsible for NMAP and his book - Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning ) the two really help you to see what's going on, on your network
Wireshark Network Analysis :The Official Wireshark Certified Network Analysis Study Guide
http://www.amazon.com/gp/product/189393 ... 1893939995
"All men can see these tactics whereby I conquer, but what none can see is the strategy out of which victory is evolved." - Sun Tzu, 'The Art of War'
OSCE, OSCP , GPEN, C|EH