This book is fun to read, with lots of great stories. The idea that much of how our minds work is based on rough probability estimates was new to me. The Kaplans describe many mental problems such as autism, as well as the strange behavior of psychopaths, as essentially disorders of a poor sense of probability in human social relations. Fascinating.
I liked the chapter on healing best. The Kaplans point out that depending on the way you report the results, the exact same study can make a drug's effect look enormous or trivial: "Program A reduced the death rate by 34 percent" and "Program C increased the patients' survival rate from 99.82 percent to 99.88 percent" makes Program A look good, but these numbers describe exactly the same program. Exaggeration of this type is all too frequent in today's medical research, and even many doctors often don't realize when they are being bamboozled. I am not kidding when I say that if more people understood what the Kaplans are getting at here, our health care system would save billions of dollars and a lot of grief. For more on this, see Hadler's book "The Last Well Person," which describes how the popularity of many expensive treatments, such as the cardiac bypass, is due to precisely this type of misleading statistics.
The book does have some equations, but they are not essential to understanding it. Feel free to skip them.
The Kaplans discuss economic growth in terms of gambling, and describe the gains from the sun each year as providing enough energy to justify between 1.5% and 2% economic growth. The Kaplans don't say where they got this figure. Economic growth being an interest of mine, I tend to disagree. Certainly economic growth figures of about this magnitude are common. However, "economic growth" is conventionally measured by GDP, a figure so inaccurate as to be almost laughable. GDP makes no adjustment for the costs of pollution, drawdown of natural resources, population growth, or reduction in quality of life, among other difficulties. More accurate economic measures, such as the Index of Sustainable Economic Welfare (ISEW) or the Genuine Progress Indicator (GPI), show that there has been little or no economic growth in the U.S. since the 1970s. Several other countries with healthy-looking GDP figures are basket cases when more accurate measures are considered. For more on this, see Herman Daly's book "Beyond Growth," or Brian Czech's book "Shoveling Fuel for a Runaway Train."
Overall, though, "Chances Are" is a highly recommended book.