It is well accepted that progress in biological and biochemical researches is based mainly on a better understanding of life processes on a molecular level. For this, modern chemical techniques for structural elucidation even of sophisticated biomolecules and theoretical and mechanistic considerations involving biological macromolecules help the understanding of structure-function relations, metabolic processes, molecular and cellular recognition and the reproduction of life. On the other hand, controlled manipulation of the struc ture of biological macromolecules and the synthesis of well designed biomimetic models are the basic tools used in bio organic chemistry, a field at the -border line between classical biochemistry and classical organic chemistry. For this, increas ing number of chemists and biochemists are studying simple synthetic molecules as models of enzyme action, ion transport across membranes and in general receptor-substrate inter action. This new series, Bioorganic Chemistry Frontiers, will at tempt to bring together critical reviews on the progress in this field. In this second volume of the series, six different active domains are covered and are presented to stress the diversity and scope of bioorganic chemistry. They include the design of artificial nucleases (Corey, Zuckermann, and Schultz), molecu lar tweezers (Zimmerman), hydrolytic cleavage with metal complexes (Chin, Banaszczyk, Jubian, Kim, and Maejen), dif ferent aspects of molecular recognition (Hamilton), supramole cular assemblies and functional models of membranes and enzymes (Murakami and Kikuchi) and the concept ofmolecu lar topology (Sauvage and Dietrich). Each subject uses a "molecular" language common to the chemist, the biologist, and the pharmacologist."