Instinct - Jeremy Robinson I have been re-reading all the books in anticipation of the new one coming out this October 2013.
I think this is one of my favorite of the Chess Team adventures. I have always been fascinated with cryptozoology and the thought of finding some primitive tribe of neanderthal type beings as in this story was very cool. In addition, I loved finding out more about the team members. This one went more into their fears and it really made me connect with them because, for all their heroism and quick thinking under pressure, you can see that they are still normal people like you and I.