In this book, both basic and advanced concepts are discussed for considering mixtures from initial exposure characterization through evaluation of risk associated with combined exposures. This book will provide an introduction to key issues and multiple options for evaluating both the toxicity of mixtures as well as the risk associated with exposure to mixtures. Additionally, promising tools adapted from other disciplines will be discussed in the context of mixtures toxicology and risk assessment. Finally, the discussion will move beyond chemical mixtures to address incorporating non-chemical stressors into toxicity studies and cumulative risk assessments.  Although exposure to multiple chemical and non-chemical stressors is the rule, not the exception, consideration of mixtures in toxicology and risk assessment continues to be a significant challenge. This book will be an essential resource for researchers and professionals in the fields of toxicology, epidemiology, exposure science,risk assessment, and statistics.