What is the theme in Deal Breaker by Harlan Coben?

Appearances being deceptive is a main theme in this book. Not all of the characters in Deal Breaker are who or what they appear to be. For instance, Esperanza Diaz, Myron Bolitar's secretary, was at one time a professional wrestler. The fact that Esperanza is also studying to be a lawyer adds a bit of humor to this fact. However, there are other characters in the narrative whose hidden personalities prove to be quite deadly.