Marc S. Williams, MD, FAAP, FACMG, FACMI is a clinical geneticist. He is professor and director emeritus of Geisinger's Department of Genomic Health. He served as the co-PI of the Geisinger eMERGE project and is the medical director of the whole genome sequencing clinical research project. His current research is focused on the implementation of genomic and precision medicine. He serves on the NHGRI Genomic Medicine working group. He has participated in the Personalized Medicine Workgroup of the Department of Health and Human Services' American Health Information Community Task Force and was a member of the Secretary's Advisory Committee for Genetics, Health and Society. He was a member of the EGAPP working group. He is a member of the American College of Medical Genetics and Genomics (ACMG) Board of Directors, serving as Vice-President for Clinical Genetics, then rejoined the board in 2019 and is the current President. He is past chair of the ACMG Committee on the Economics of Genetic Services and founded the ACMG Quality Improvement Special Interest Group. He is a member of the Scientific Advisory Board of the Clinical Pharmacogenetic Implementation Consortium (CPIC) and a member of the CPIC informatics committee. He recently joined the Scientific Advisory Boards of the NIH Undiagnosed Diseases Project, and Online Mendelian Inheritance in Man. He has authored over 200 articles on a variety of topics including the economic evaluation and value of genetic services, implementation of genomic medicine, and the use of informatics to facilitate genomic medicine and precision health.