4 Use of Graph-Theoretic and Geometrical Molecular Descriptors in Structure-Activity Relationships SUBHASH C. BASAK, GREGORY D. GRUNWALD, and GERALD J. NIEMI Ostensibly there is color, ostensibly sweetness, ostensibly bitterness, but actually only atoms and the void. GALEN (Nature and the Greeks , Erwin Schrödinger, 1954) 4.1. INTRODUCTION One of the current interests in pharmaceutical drug design, 1–20 chemistry, 21–40 and toxicology 41–53 is the prediction of physicochemical, biomedicinal, and toxicological SUBHASH C. BASAK, GREGORY D. GRUNWALD, and GERALD J. NIEMI Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota at Duluth, Duluth, Minnesota 55811. From Chemical Topology to Three-Dimensional Geometry, edited by Balaban. Plenum Press, New York, 1997 73