Dr. Cynthia Rider is a toxicologist with the National Toxicology Program, National Institute of Environmental Health Sciences, where she has been actively involved in mixtures research including work with polycyclic aromatic hydrocarbons and herbal products. She received her B.S. from Tulane University and her Ph.D. from North Carolina State University in Environmental Toxicology. She completed post-doctoral training in the Reproductive Toxicology Branch of the National Health and Environmental Effects Research Laboratory, U. S. Environmental Protection Agency (EPA) and the Nicholas School of the Environment at Duke University. Dr. Rider has been an active member of the mixtures community through reviewing papers, serving on an EPA panel on cumulative risk assessment of phthalates, and developing mixtures-related scientific program proposals for Society of Toxicology annual meetings. Jane Ellen Simmons is Chief of the Pharmacokinetics Branch, National Health and Environmental Effects Research Laboratory, US EPA. She received an MSPH in Environmental Management and Protection and a PhD in Toxicology from the Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina at Chapel Hill. Her research focus areas include: models, methods and approaches for both defined mixtures and environmentally realistic complex mixtures; integrating chemical and toxicological evaluations of chemical mixtures; and much more. She is a Diplomate of the American Board of Toxicology. She co-chaired the International Toxicology of Mixtures Conference and has served on the HiWate Science Advisory Board, on review panels for the Food and Drug Administration and North Carolina State University and Advisor to the US EPA RTP Chapter of the National Training Leadership Organization. Dr. Simmons has also authored more than 90 peer-reviewed journal articles and 15 book chapters and reports.