Still's research is supported by the Synthetic Organic Program. A professor of Chemistry at Columbia University, Still is studying how to prepare and computer-model structures and reactions of complex organic molecules. His work has already had impact on how chemists design and analyze molecular structure, and his studies continue to lead the way in this very important area. The objectives of this project are: 1) to prepare a series of conformationally restricted host molecules with three- dimensional binding sites, 2) to study their geometries and binding properties with guest molecules, and 3) to use the data obtained to test and evaluate a computational method for predicting binding properties.