The current text provides sufficient background in understanding why behavior occurs to facilitate the reader’s capability to develop intervention strategies that make functional sense. In order to design and implement effective intervention strategies, the ability to decode the function of chal- lenging behavior is a requisite. To acquire such skills requires a comprehen- sive approach to skill development. Too often, classroom personnel are taught a few tricks and then encouraged to go and try them. Changing behavior is not a matter of a few tricks! Rather, the professional repertoire needed requires a thorough understanding and analysis of the role of the social environment, both before and after the behavior. Therefore, I have taken painstaking efforts to make sure that this text is not a “cookbook” of menus to try. In contrast, this text provides a conceptual basis for under- standing why certain behaviors occur under specific conditions. After read- ing this material, I am sure you will have a finer appreciation for the role of a behavior’s antecedent and consequent conditions.