Free Radicals in Drug Research, M.B. Roberfroid, H.G. Viehe, and J. Remacle. The Parametrization of Lipophilicity and other Structural Properties in Drug Design, H. Van De Waterbeemd and B. Testa. Structure-Activity Relationships and Mechanisms of Action of Antibacterial Sulphanilamides and Sulphones, P.G. De Benedetti. The Stereoelectronic Effects at the Opiate Receptor: their Influence on Affinity and Instrinsic Activity, V.M. Kolb. Drug Action and Cellular Calcium Regulation, R.A. Janis, P.J. Silver, and D.J. Triggle. Subject Index. Cumulative Index of Authors. Cumulative Index of Titles.