Prologue: Over five years ago, Arizona embarked on a program to combine elements of competition with provision of health care for the state's poor population. This experiment, the Arizona Health Care Cost Containment System (AHCCCS), has been closely monitored by the health policy community and has received conflicting evaluations from its observers. AHCCCS has been called a “remarkable success” by some health analysts, while others, including lead author Bradford Kirkman-Liff, have noted that the program may have led to increased problems with access to health care for the poor ( Health Affairs , Winter 1985). The General Accounting Office recently reported that AHCCCS was plagued with such problems as poor management and implementation, bankruptcies of some contracting health maintenance organizations (HMOs), and little monitoring of data. In this article, the authors trace the evolution of AHCCCS and discuss the problems that have haunted the program. If a lesson is to be learned, it is that “the environment is not static for these programs,” said coauthor Jon Christianson. The health care organizations that expected to be the major players in AHCCCS are not. Today's Arizona program operates somewhat differently and does not meet the same objectives of true competition as originally envisioned by the program's architects. Bradford Kirkman-Liff, an associate professor at Arizona State University, received his doctorate in public health from the University of North Carolina. Christianson, who wrote about the Arizona experiment in its early stages for Health Affairs in 1983, is a professor in the Division of Health Services Research, University of Minnesota School of Public Health. Formerly on the faculty at the University of Arizona, he holds a doctorate in economics from the University of Wisconsin. Tracy Kirkman-Liff is a health care consultant and former director of the Arizona Coalition for Cost-Effective Quality Health Care. The Kirkman-Liffs are currently on a one-year leave to Erasmus University, Rotterdam, The Netherlands, and are helping to develop HMO-like systems there.