In the world of health policy, we seldom have the luxury of testing our hypotheses with a `gold standard' randomized controlled trial. Instead, we must make due with observational evidence, finding creative ways to take advantage of existing circumstances. Thus, our richest source of knowledge is our own experience and the experience of others.

In Unfiltered: Conflicts Over Tobacco Policy and Public Health, Eric A. Feldman and Ronald Bayer have collected a series of essays about how eight countries—the United States, Japan, Canada, Australia, Great Britain, France, Germany, and Denmark—responded to the tobacco epidemic. The book is the outcome of a project supported by the Robert Wood Johnson Foundation, which included three meetings over 18 months among an international and interdisciplinary panel of political scientists, sociologists, historians, legal scholars, and public health experts. As the title suggests, the editors sought to provide an objective, `unfiltered' analysis of the development of tobacco control policies, free of ideology or preconceived assumptions.

Feldman and Bayer instructed authors to address three key policy questions in particular:

How far should controls over advertising reach?
Should there be extensive restrictions on smoking in public settings?
How might taxes on tobacco serve the public health?

The book includes a chapter for each of the eight national case studies, each of which reads like its own mini-history of tobacco control. These are readable and engaging blow-by-blow accounts of political and legal battles over tobacco control policies. Each could undoubtedly fill a volume on its own.

The most striking conclusion from this group of case studies is the degree of similarity across them. It is essentially the same plot, unfolding over and over again with some slight variations in the timeline and cultural context. As evidence of the health effects of cigarette smoking mounted, governments responded by providing authoritative information to consumers in the form of health warnings. In the face of possible advertising regulations, tobacco companies developed voluntary advertising codes to preempt legislation. While these early efforts focused on adult smokers and consumer information, subsequent more stringent regulations focused on the effects of cigarette smoking and advertising on children and non-smokers. Stronger advertising controls and prohibition of smoking in many public spaces was the result. The path to the current policy regime, in each case, was a long and indirect one, pitting the interests of politicians, government officials, the tobacco industry, and the medical profession against each other with sometimes unpredictable results.

At the same time, of course, there are important differences in how these eight nations responded to the tobacco epidemic. Some countries which were slow to respond to the evidence against cigarettes subsequently became world leaders in tobacco control, as evidenced in Australia's comprehensive advertising restrictions and Canada's graphic warning labels. At the same time, while France's loi Veil, the country's first tobacco control law, was far ahead of its time in 1976, it was in practice, writes sociologist Constance Nathanson, "little more than an intellectual exercise, honored far more in the breach than the observance." (145).

The volume also includes three cross-national analysis chapters. Anna Gilmore and Martin McKee discuss tobacco control policy in the European Union, utilizing tobacco industry documents to study tobacco industry strategies in Europe, historian Allan Brandt discusses differences in cultural and social attitudes regarding cigarette smoking, and Theodore R. Marmor and Evan S. Leiberman, experts on comparative politics and public policy, draw some cross-national conclusions.

A running theme across these eight countries is a seeming conflict between the values of beneficence and autonomy. While there was widespread agreement across the eight countries that governments have an obligation to intervene to protect public health, there were substantial differences over how and to what extent governments should regulate individual behavior. Ultimately, the differences between countries were not over the science of the health effects of tobacco smoking or even the justification for public health action. Rather, the differences were primarily over what methods of intervention were most appropriate to achieve public health goals while preserving liberties.

But what do these differences teach us? Are there more general lessons to be drawn from this group of case studies? In their comparative analysis chapter, Marmor and Leiberman describe differences in the strength of tobacco control regimes. They classify Australia, Canada, Denmark, and Great Britain as "high-control regimes", while Japan is low control and France, Germany and the US are in the middle. So what causes a nation to be towards one end or the other on the spectrum? Cultural differences and differences in political structures surely play a role here, suggest Marmor and Leiberman. For example, in federalist states (Canada, the US, and Australia) local activism has played a more important role in driving policy, while in centralized states, elite groups (such as the medical profession) have had more influence. But, in the end, no single variable can fully explain the diversity in strength and type of tobacco control policy regimes.

The book does suffer from some significant omissions. For example, while the title refers to conflicts over tobacco policy, the book is limited to cigarettes, not smokeless tobacco or other forms of tobacco use. More importantly, the book omits the regions of the world which will be most affected by the tobacco epidemic in the future—South America, Southeast Asia, and Africa. The editors do not comment on how the eight nations represented were selected or how the lessons from these case studies might, or might not, translate to other parts of the world. Also absent is any significant discussion of the Framework Convention on Tobacco Control and its potential impact on tobacco control at the global level.

Nevertheless, the case study approach provides an excellent example of how astute observation of past experience can inform policy efforts. Overall, the book is accessible and engaging and provides excellent material for students and practitioners of public health policy who want to understand the challenges in translating evidence into action.

Mark Parascandola is an epidemiologist with the Tobacco Control Research Branch of the National Cancer Institute.