Collision Board is the study of realistic Self Defense.  It covers material concerning the most important things a person needs in basic self-defense, so it has things that a beginner needs to know, and at the same time, it deals with advanced aspects such as how to finish a fight.  A person interested in self-defense learns important things but things that don't require years of skill development.  They try to affect an attacker and possibly get away or get help.  For the experienced martial artist, this board gives one thing to efficiently finish a fight.  This, of course, builds off of all the basics of the CBS.