Distinct types of activity in the field of applied behavior analysis are noted and discussed. Four metaphorical types of activity are considered: prospecting, farming, building, and guiding. Prospecting consists of time-limited exploration of a variety of beaviors, populations, or settings. Farming consists of producing new behaviors in the same setting using independent variables provided by the researchers or normally available in the setting. Building consists of combining procedural elements to create new programs or systems or to rehabilitate aspects of existing programs. Guiding involves pointing out connections between the principles of human behavior and the problems, populations, settings, and procedures with which researchers are (or could be) working. Advantages of each sphere are noted, and benefits of this division of labor to the field as a whole are discussed.