This series of papers was presented in a symposium on behavior therapy. Each paper represents a separate study focusing on one aspect of behavior modification. The issue of reinforcement is prominant with regard to its type and source. Methods of self-reinforcement and older-peer modeling are studied. The suggestion that subjects who reinforce coverants (covert operants) which are incompatible with certain personal problems will consequently modify their maladaptive behavior is tested in one study and a modification of this theory is the basis of another. Individual papers include: (1) "In Vivo Emotive Imagery: An Experimental Test;" (2) "Behavioral Self-Control of Chronic Fingernail Biting;" (3) "Weight Loss Through Variations in the Covariant Control Paradigm;" (4) "A Test of the Incompatible Coverant Assumptions;" and (5) "The Effect of Older-Peer Participant Models on Deficient Academic Performance." (RWP)