This issue of the Health Care Financing Review focuses on issues and advances in measuring and improving the quality of care, particularly for Medicare and Medicaid beneficiaries. Discussions of quality-related topics are especially timely, given the growing and widespread interest in improving quality in the organization, financing, and delivery of health care services. This article has several purposes. The first is to provide a brief description of some of the causes underlying the growth of the health care quality movement; the second is to provide a contextual framework for discussion of some of the overarching themes that emerge in this issue. These themes include examining conceptual issues, developing quality measures for specific sites and populations, and creating or adapting data sets for quality-measurement purposes.