Like the health economics professor that he is, Richard Scheffler takes readers of his most recent book into a virtual classroom, offers up an analysis of how many doctors are enough, and spices the mix with the opinions of respected peers. But, ultimately, he provides no definitive opinion on the question that begs for an answer: how many physicians would be an adequate number to care for a more demanding baby-boom generation, to cope with an explosion of chronic illness, and to prepare for a population that is growing at the rate of about twenty-five million people every decade? Although Scheffler offers different takes on the contentious issues surrounding physician supply, he is reluctant to offer a definitive view on the appropriate number. As he notes, previous analyses have declared with confidence that the United States faces a surplus (or a shortage) of physicians given societal trends at the time. Most (if not all) of the predictions have been proved wrong, and accurately forecasting the right number remains one of the many challenges facing our troubled health care system. Vast differences of opinion continue to provide grist for the continuing debate.1 Scheffler does state a preference to err on the side of too many rather than too few doctors and to modestly increase the number of primary care physicians. But in his final chapter he says, “Forecasting efforts in the past have missed the mark and even led to strategies that caused problems over the long term. Therefore, as a health economist, my inclination is to summarize the input on all sides and leave it at that” (p. 191). (Of the twenty-seven health policy experts he interviewed, most who addressed the question of whether more doctors should be trained opposed an increase in physician supply or offered cautionary comments.) Scheffler’s book is a useful addition to the literature because he probes the extensive relationship between the market and physician supply in an interesting way. His conclusion is that the market indicators—including physician income, selection of specialty, geographic distribution of doctors, and numbers of nonphysician clinicians in the workforce—all respond rapidly and predictably to economic incentives in the marketplace. Morever, he says, the connection between the market and these indicators was tighter during the heyday of managed care than before. Scheffler intends for his book to help policymakers and other interested parties better visualize the economic framework that underlies health care delivery and the supply of physicians. He dwells on the role managed care in redistributing market power between physicians and health insurers. He writes: “The incentives that were applied under managed care were intended to diminish the moral hazard that encouraged excessive services in the fee-for-service environment and resulted in fast-increasing costs for everyone.” As a consequence, physicians “saw their professional autonomy, their income, and their economic power greatly reduced. Market power shifted to payers and away from doctors” (p. 19). B o o k R e v i e w s