I argue that our field has two subject matters that are distinct in several ways. Each is derived from, and contributes to, the foundation science and epistemology associated with behavior selection. The research and application areas are not the typically touted applied, experimental, or theoretical areas of behavior analysis. First of all most of the empirical research in both subject matters employs the experimental method and most draw on theoretical inquiry. The differences that I want to describe occurred to me as I sought to identify which of two Spainish phrases best represented our science--Analisis de el Comportamiento or de La Conducta. I found the distinction between the meaning of the two compelling because they clarified issues that I and my colleagues had faced in the more than 20 years of building schools that educated the whole child based entirely on scientific procedures (Greer, 2002). To me, de el appeared to concern behavior broadly construed as in the the behavior of matter or species and it's origins, whereas analisis de la was about well. Analisis de la conducta identifies the variables associated with: behaving fluently, the molecular and molar contingencies associated with existing operants, or conducting one's self consistent with the best interests of the individual and culture. Analisis de el comportamiento appeared to concern how behavior functions originate, operants or higher order operants, and how they can be induced when they are missing. Of course, both subject matters in our science are really about the effects or funtions of behavior, rather than behavior per se. Other behavior scientists are concerned about the topography of behavior ranging from muscle movement to blood flow in parts of the brain. I am sure that my simplistic definition of the two Spanish terms would not hold up to the scrutiny of someone who is really expert in Spanish. But my musings of the two terms led me to reflect that the two definitions I had extrapolated really had to do with an evolution in the way I was beginning to view our science. It seems to me that when operants are already in the individual's repertoire the fundamental concern is to identify the contingencies that evoke the behaviors--the existing controlling variables for behavior whether we call the behavior appropriate or bad. They are the preverbial behaviors. On the other hand it seemed to me that when the objective of scientific inquiry or application is to create or induce new operants or higher order operants different tactics and strategies are needed. Thus, when we seek to teach children to use language functionally, solve problems, enlarge their community of or acquire academic literacy, to name a few examples, we are engaged in teaching new operants or higher order operants (Catania, 1998; Greer, 2002; Hayes, Barnes-Holmes, & Roche, 2000; Skinner, 1968). When we seek to identify and form new repertoires the verb teach seems eminently suitable, while the verb train is suitable for arranging controls for existing repertoires. Examples of research concerned with identifying the controlling variables for behaviors that exist in the individual's repertoire includes but is not limited to: the effects of schedules of reinforcement on key pecking (after the pigeon has learned to peck on the key), or the source of tantrums that have already been unwittingly shaped by children's caretakers. Such efforts also include assessments of reinforcers, identification of collateral behaviors (i.e., adjunctive responses), isolation of existing generalized stimulus control, the effects of drugs on performance, or the identification of conditioned eliciting stimuli associated with emotional responding. There is a long history in our science for this pursuit (Catania, 1998). Still other examples of the analysis of the controling variables for performance in applied settings concern the identification of tactics for classroom management (i. …