To maximize the use of the resources of the newly formed NCI Chemical Biology Consortium (CBC), especially the high throughput screening of diverse chemical libraries, and increase the potential hit rate, it will be necessary to augment current trans NIH chemical libraries, e.g. NIDDK (~ 2,500 compounds), NCI, DTP (~180,000 compounds), NIH Roadmap (>280,000 compounds) with compounds and libraries that are only available from external sources.