Having argued in Part One against extensive judicial or regulatory interference with private personnel credentialing in the health care field, this Article now shifts its focus to emphasize the anticompetitive hazards inherent in credentialing as practiced by professional interests. Competitor-sponsored credentialing is shown to be a vital part of a larger cartel strategy to curb competition by standardizing personnel and services and controlling the flow of information to health care consumers. Instead of altering the conclusions reached in Part One, however, Part Two sets forth a new and hitherto unexplored agenda for antitrust enforcement, one that the authors believe will increase the quantity and quality of information available to consumers and offer a fairer competitive environment to individuals and groups disadvantaged by the denial of desirable credentials. The specific targets singled out for antitrust scrutiny are (1) the practice of "grandfathering," by which new candidates for credentials are required to meet tougher requirements than were met by existing credential holders; (2) agreements to standardize educational programs if they go beyond setting and applying accrediting standards and impair the freedom of institutions to decide independently whether to offer unaccredited training; (3) agreements by which independent certifying or accrediting bodies limit the nature or scope of competition among themselves; and (4) mergers and joint ventures in credentialing and accrediting. The legal theory supporting antitrust attacks in the latter two categories is strengthened by the apparently original insight that commercial information and opinion are themselves articles of commerce such that agreements and combinations restricting their nature and output can be characterized as restraints of trade. Among the many self-regulatory institutions in the health care field whose operation or sponsorship is called into question by the analysis herein are the leading medical specialty boards, the Liaison Committee on Medical Education, various accrediting and certifying bodies in the allied health occupations, and the Joint Commission on Accreditation of Hospitals.