The postdoctoral fellowship afforded an opportunity for the author to engage in an intensive year of training and research in structural learning at the University of Pennsylvania and Standford University. The basic research goal was to clarify some of the fundamental problems involved in the teaching and learning of subject matters and the assessment of knowledge--both with the emphasis on mathematics. Results of the year's study include a textbook for teachers entitled "Mathematics: Concrete Behavioral Foundations for Teachers" and several monographs. (The major portion of the document consists of three monographs written during postdoctoral fellowship year: 1) "Deterministic Theorizing in Structural Learning: Three Levels of Empiricism"; 2) "The Role of Rules in Behavior: Toward An Operational Definition of What Rule Is Learned"; 3) "A Theory of Mathematical Knowledge: Can Rules Account for Creative Behavior?".) [Due to poor quality of the original document, it is not available from EDRS, but may be obtained on loan from the Clearinghouse on Teacher Education.] (RT)