In the movie "Thank You for Smoking," Aaron Eckhart plays tobacco industry spokesman Nick Naylor, a guy so charismatic it's impossible not to like him even as he pursues deals to increase smoking in films and pays off a cancer-stricken Marlboro man to keep quiet.

As the Big Tobacco lie begins to implode, Naylor finally admits that, of course, he thinks smoking causes cancer, and then, in a monologue that brings down the house, explains that he, and every other citizen, should have the right to take that risk.

It's a classic American idea -- freedom of choice.

But as Devra Davis' new book, "The Secret History of the War on Cancer," makes clear, choice is impossible without information. The book is a must-read for those concerned about their own health or that of their loved ones. It's also fascinating.

Describing 70 years of cancer research, Davis moves fluidly between personal recollection and analysis of an extensively documented, if until now hidden, historical record.

She discloses a revolving door between industry and cancer education and research organizations. The economic and political maneuvering between them kept knowledge of the carcinogenic properties of many common compounds hidden from the workers and citizens affected by them.

Throughout, she argues that a national focus on curing cancer left much knowledge on how to prevent it unheeded.

The book is largely chronological. The early research Davis covers is so unfamiliar today that it's occasionally difficult to see where she's going, such as when she examines the health policies of Nazi Germany.

But even apparent detours circle back to the main point. While Davis notes that Nazi experiments on tobacco and many chemicals were clearly immoral, they yielded a wealth of information on exposure risks that the Allies ignored, even as they assimilated Nazi advances in other areas, such as rocket science.

Davis also chronicles the little-known early years of the American Cancer Society, explaining how the corporate ties of board members brought considerable fund-raising acumen and a resultant bigger budget for research into cures -- but at the same time prevented the organization from recognizing smoking as a cause of cancer.

Throughout, Davis sketches the personalities that shaped the history and also weaves in memories from her professional development as well as her family life. Both of her parents died of cancer, her father from multiple myeloma, a cancer of the bone marrow, her mother from stomach cancer.

An epidemiologist, Davis is now the director of the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute.

Epidemiologists spend their careers studying life in the real world, trying to tease out the effects of specific changes and exposures. This work is hard to do, and Davis doesn't underestimate the complexities of risk and the impossibility of assigning a single cause to one case of a disease.

However, she argues that there is often enough information to make important decisions about health and safety, even taking all that complexity into account. In many ways the book is a call to arms.

Davis on tobacco:

"The dramatic drop in smoking-related deaths is no accident. This success is also exceptional, because it stems from controlling a well-defined hazard that was known to be a problem long before society finally acted. But those who forced us to wait for incontrovertible proof exacted a heavy price in premature deaths."

Even more disturbing than the relatively well-known history of tobacco is Davis' analysis of how tobacco's success shaped the actions of other industries, such as the artificial sweetener aspartame, that created known or suspected carcinogens. Davis also describes the risk posed by diagnostic procedures such as CT scans, which dose the body with as much radiation as several hundred chest X-rays.

And she adroitly deconstructs studies that supposedly document the safety of cell phones, explaining how the methodology of industry-funded research is biased against finding problems.

There will certainly be those who argue that such talk is alarmist, but, as Davis puts it:

"We have seen readily how some people in industry, whether tobacco, asbestos, benzene or vinyl chloride, understood risks long before the rest of us were able to learn about them. We know of many instances where insurance companies tracked health hazards for years as claims mounted and reports of various ailments accumulated, without letting workers know the dangers they faced."