In a July 25th Health Affairs web exclusive, Bob Berenson, Tom Bodenheimer and Mai Pham tracked the emergence of specialty-service lines as the primary basis for competition among health care providers. The authors describe the emerging practice of hospitals and physicians to organize and market services based on specific diseases, organ systems, and population and find that competition for control of these specialty services is causing a growing battle among physicians and hospitals. Market participants, including health plans, charge that this competition is contributing more to an inflationary arms race rather than cost-reducing price competition. (Health Affairs Web Exclusive, July 25th, 2006)