The lack of adherence to medication is a growing public health problem worldwide and is costing many patients their good health and healthcare systems billions of dollars. Analytical Chemistry for Assessing Medication Adherence introduces the concept of medication adherence/compliance and reports international perspectives on medication adherence while highlighting its importance. It then describes the opportunities for analytical chemistry to assess medication adherence and thereby provide an evidence base for clinicians to improve patient health outcomes. The authors highlight the strengths and weaknesses of each of the analytical techniques cited in addition to categorizing the findings in terms of the biological samples used to assess adherence and identifying methods to extract biological samples prior to analysis. The final chapter provides the authors’ perspective in this area, emphasizing the importance of medication optimization for individual patients. Published by Elsevier in partnership with RTI Press, Analytical Chemistry for Assessing Medication Adherence is the second volume in the Emerging Issues in Analytical Chemistry series, which is edited by RTI’s Brian F. Thomas.