I read this book on decision making as part of my on-the-job studies of the field of risk management. It is a superb examination of many current practices in risk that aims to find a sort of middle path. The author explains why he eschews complex algorithms in favor of heuristics, and avoids complex "risk-based" structures in favor of more simple practices.
It's a convincing read, especially when he points to the poor track record obtained using mathematical means to predict outcomes, the failure by most non-specialists to even comprehend estimates, and the obscene mis-use of dangerous diagnostic tools (e.g. cancer-causing X-ray machines) for routine examinations. It's also a highly readable examination of the problem-space. Gigerenzer is one of those irreverent Germans who uses a direct wit to point out that countless emperors wear no clothes. (Sadly, the risk field is crowded with these.)
You can get a good sense of the material covered in this book by viewing some of Gigerenzer's talks on Youtube. Which I've done, for instance, while ironing shirts for the coming week.
I enjoyed this book so much that I intend to re-read it.