It is the purpose of this review to present an integrated, selective, and constructively critical summary of major current trends in behavioral pharmacology. This rather formidable task has been accomplished in at least two relatively recent reviews by Dews & Morse in 1961 (1) and Cook & Kelleher in 1963 (2). The excellence of these contributions lightens the literature-survey burden prior to these dates. Our coverage of major trends, involving the effects of specific classes of drugs upon behavior, pharmaco logical analysis of biochemical-behavioral interrelations, and drug-behavior interactions, will emphasize developments in these areas as they have emerged since the prior reviews in this series.DOPA (!3-3,4-dihydroxyphenyl-L-alanine); DRL (differential reinforcement of spaced responses); EKG (electrocardiogram); FI (fixed interval schedule); FR (fi xed ratio schedule); LSD (lysergic acid); SMA (spontaneous motor activity); and VI (variable interval).