This book does two important things - it challenges the reader to really think about the causes of things, and it makes modern economic thinking interesting and accessible to the mass audience. It's also a good, fun read, and for all these reasons it should be applauded.
In this book Steven Levitt develops ideas about a number of aspects of economic and social development which challenge received wisdom. He then both challenges traditional analyses, and offers solid support for his theories using detailed analysis of a number of unusual but highly reliable data sources.
For example, he attributes the dramatic fall of crime rates in the USA in the 1990s to greater access to abortion 20 years earlier, rather than traditional explanations like better policing. Drawing on a number of unimpeachable data sources he provides strong support for his hypothesis over more common ones.
Another fascinating chapter analyses the economics of drug dealing, and concludes that most crack dealers would be better off with regular minimum-wage jobs.
However, these are the high points, and towards the end the book starts to feel like the authors didn't have enough material for a 200 page book. There's a fair amount of repetition, and the later chapters start to feel a bit light. The last chapter, on trends in children's names, is really rather boring and tells us very little of interest.
This is a shame, because the core of the book is excellent. It will hold your interest, but don't expect a lot of pages for your money. Maybe the authors are genuinely very clever.