The makers of public health policy face enormous challenges in the twenty-first century. In the past, their field has been imprecisely defined, deeply conflicted, poorly organized, and constantly changing. Lines of responsibility within the field are blurred at best, and groups with similar goals sometimes find themselves at cross-purposes. In the United States, state and local agencies interact with each other, with federal programs, and with powerful private interests. Many decisions that profoundly affect the health of the public are made for reasons largely unrelated to public health per se. Since the human and financial stakes involved in public health policies are immense, these challenges are, to say the least, serious issues. Underlying this volume is the belief that historical analyses and international perspectives can help policymakers understand, and hopefully begin to address, some of those old challenges in new ways.

The health-care system was one of the most visible and contentious battlegrounds on which the social conflicts of the 1960s unfolded. To an unprecedented extent, health status—especially the stark disadvantage in access and outcomes for racial and ethnic minorities and the poor—became an object of public and governmental concern during the Great Society era, as clinicians, community activists, politicians, and policymakers sought to create new models of medical care that were more equitable and efficient than those of the past. The social science theories that informed the ambitious programs of Lyndon Johnson's administration gave an imprimatur to the idea that illness was both cause and consequence of the “cycle of poverty.”

During the 1980s illegal drug use in Britain appeared to be increasing at an alarming rate and spreading across the country on an unprecedented scale. An apparent growth in the use of heroin caused particular concern: the number of known heroin addicts rose from just over two thousand in 1977 to more than ten thousand by 1987. Moreover, heroin use was being reported in urban areas throughout the country. This was in contrast to previous decades, when it was thought that drug use was largely confined to London. By 1985 the Conservative government was able to assert that “the misuse of drugs is one of the most worrying problems facing our society today.” Growing fears about drug use prompted a flurry of activity from both central and local government, from law enforcement bodies, voluntary organizations, and health professionals.

Over the past decade, evidence-based medicine (EBM) has become the standard for medical practice.1 Evidence-based practices have been established in general medicine and specialized fields; new evidence-based journals have been launched.2 Although its roots can be found in mid-nineteenth-century medical philosophy, contemporary EBM was largely developed by the clinical epidemiology program at McMaster University in 1992.3 According to the McMaster manifesto published in JAMA, EBM “deemphasizes intuition, unsystematic clinical experience, and pathophysiologic rationale as sufficient grounds for clinical decision-making, and stresses the examination of evidence from clinical research.”4 The most frequently cited definition of EBM is reliance on the “conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients,” based on an integration of “individual clinical expertise with the best available external clinical evidence from systematic research.”5 However, as Stefan Timmermans and Aaron Mauck recently observed, EBM “is loosely used and can refer to anything from conducting a statistical meta-analysis of accumulated research to promoting randomized clinical trials, to supporting uniform reporting styles for research, to a personal orientation toward critical self-evaluation.”6

Dangers to life and health abound. Even among the subset known to medicine and science, however, there is no guarantee that any particular danger will rise to the level of a recognized public health problem or elicit a response from the makers of public policy. The path from knowledge to policy is not straightforward; scientific consensus does not lead automatically to policy consensus. Judgments of what dangers should be most feared, how to explain them, what to do about them, and even whether they are public health problems at all are the outcome of social processes. A couple of examples may help to clarify these points.

The history of policies affecting individuals with intellectual disabilities has received attention from social historians interested in gender and family, from the emerging discipline of disability studies, and from scholars interested in the evolving role of eugenic arguments and medical genetics in American life. That history has received less systematic study from the community of policy analysts and scholars traditionally concerned with welfare, poverty, and public health. This is unfortunate because the history of policies affecting intellectual disability offers at least three significant lessons.

Normally we do not think of living organisms as machines or as relays in complex, tightly coupled technological systems. Nonetheless, in recent years this is precisely the manner in which many environmental historians have come to approach the study of certain organisms and their natural or anthropogenic environments. Over the millennia and across the globe, humans have so manipulated certain organisms that they have come to exist solely as parts of technological systems or industrialized chains of production and consumption. Technological artifacts are, of course, only nature refashioned: nonetheless, modern industrialized societies tend to view themselves as gradually distancing themselves from, replacing, or, in some instances, even killing nature with their advanced technologies and gadgetries, when actually they are only refashioning their inseparable relationship to it.