This Workshop, under the auspices of the NATO Advanced Research Workshop program, was organised to review the current status of research into redox-activated compounds particularly bioreductive drugs, and their applications in various fields of medicine, both as diagnostic and therapeutic agents. The Workshop brought together key workers in this currently expanding field of research, i.e. clinici- ans, pharmacologists, biochemists and molecular scientists. The programme consisted of several sections including general review lectures, presentations of laboratory-based and clinical research, some poster presentations and general "round table" discussions. The topics ranged from oxygen effects in biological processes, the nature and function of redox proteins particularly those involved in drug activation, the bioactivation of drugs used as sensitizers in radiation oncology, novel approaches to anti-cancer chemotherapy, anti-bacterial agents, non-steroidal anti-inflammatory drugs, anti-oxidants and varous clinical applications of chemical modifiers. G.E. ADAMS A. BRECCIA E.M. FIELDEN P. WARDMAN v ACKNOWLEDGEMENTS The Organisers gratefully acknowledge the following for their generous financial support: ARW-NATO Comune di Fermo, Italy Cas sa di Risparmio di Fermo Istituto di Scienze Chimiche, Bologna, Italy Pharm. Group ALFA, r, assermann, Schiapparplli, Italy Sadam Indu tr ie.-' Pharmex Corp., Bologna, Italy vii CONTENTS Characteristics of Hypoxic Cells that Enhance their Susceptibility to Chemical Injury . . . .