This document discusses different behavioral styles - Dorian, Indy, Sandra, and Crystal - and principles for understanding behavioral styles. It introduces four friends with different personalities - Dorian is direct and action-driven, Indy wants to have fun, Crystal needs everything to be perfect, and Sarah hopes everyone will get along. It then describes each style's key traits and provides seven principles for using behavioral styles, such as understanding your own style, recognizing others' styles, and treating people how they need rather than how you need. The document ends by asking how DISC can be used and about the reader's own behavioral style.