As everyone knows there's a ton of information out there regarding pen testing.  To stimulate some conversation, I'd like to throw out this scenario...

If you were mentoring someone through the OSCP who had minimum pen testing experience and could only give them 1 book (or 1 website reference) as supplemental material for the course, what book/website would you suggest?

My suggestion would be "BackTrack 4: Assuring Security by Penetration Testing".  Even though the latest BT release is v5, I still believe this book is extremely relevant for a beginner pen tester.

Thoughts?