Howard Rachlin (1978) 'Behavior and Learning' is a good place to start. Barry Schwartz (1989) 'Psychology of Behavior and Learning' is another good introduction to behavioral theory. It has moved a long way since Skinner and Pavlov. The trends are much more grounded in information processing models in associative and operant learning (not to be confused with the psuedo-cognitive learning models of Beck and what might be called the 'Stanford' group of Bandura, Michenbaum, and Mahoney). What is taught as behavioral intervention in many schools of social work and in psychology/psychiatric programs has a tentative linkage, at best, to behavioral theory (as in the Journal of the Experimental Analysis of Behavior). This might be the culmination of the technical drift that Stephen Hayes and others have described.