The focus of this research will be to expand the number and range of small molecule libraries using the `libraries from libraries` concept. For example, polyamine libraries generated by the exhaustive reduction of peptide libraries can be readily converted to libraries of hydroxylamines, nitrosamines, peptide ureas, and/or heterocyclic imidazolidones. These, in turn can be used to generate other libraries. An ever-expanding combination of such different chemical alterations permits the generation of a `toolbox` of chemical transformations capable of producing immense diversities of compounds. With this award, the Synthetic Organic Program is supporting the research of Dr. Richard A. Houghten of the Torrey Pines Institute for Molecular Studies. Dr. Houghten will focus his work on increasing the range and repertoire of soluble peptide, peptidomimetic and organic synthetic combinatorial libraries and to improve the methodologies used for their synthesis. Combinatorial libraries have broad utility for the de novo identification of potent analgesics, novel and highly active antimicrobials, enzyme inhibitors and highly specific antigenic determinants.