This free two day workshop will cover a broad range of critical concepts underlying assay development and implementation for high throughput screening (HTS) and lead discovery projects. Many of the methodologies successfully implemented in such projects have established a good deal of “tribal knowledge” within the pharmaceutical industry which is not readily found in a classroom or the literature. This tribal knowledge, developed over decades, has been transferred into detailed chapters within the Assay Guidance Manual to facilitate reproducible and robust assays that can identify the most promising compounds for the development of molecular probes or clinical candidates. The workshop will provide participants with a broad, practical perspective on assay development so that they can (1) improve research projects involving drug discovery, and know where to find further information (2) identify reagents, methods and instrumentation that are well suited to robust assays and (3) develop robust assays and the required counter and secondary assays for targets of interest.