This chapter gives a general outline of Powers' vision of a research program aimed at testing his PCT model of purposeful behavior. The program involves gathering data on the variables organisms control when they are carrying out various behaviors and classifying those variables into types. The goal of the program is to see if the variables organisms actually control correspond to the types of variables controlled and the hierarchical relationships between them in the PCT model of behavior. Once it is validated by testing the PCT model can be used as a basis for understanding behavior opening up the possibility of developing better ways of dealing with the living control systems that are often the ones most prominent in our lives - other people.