Freakonomics is an excellent book. It is veritably called "Freakonomics" as it uses tools that economists generally use to investigate problems that do not seem to be in the purview of Economics. The author investigates several topics both intractable and trivial by analysing huge chunks of data to identify patterns. "People may lie but data do not." is Mr Levitt's argument and he proves it conclusively. Some of the topics he has covered in this book are,

1)What makes a perfect parent?
2)What defied the popular belief and contributed to the decline of crime in the 90s?
3)Match fixing among Sumo wrestlers in Japan?
4)Cheating by teachers
5)How sincere can real estate agents be?
6)What brought the Ku Klux Klan down?
7)Why do crack dealers live with their mothers?

Undoubtedly, Mr.Levitt is a maverick and he makes seemingly meaningless piles of numbers tell tales that turn conventional wisdom on its head. What i felt most striking was his reasoning that the decline of crime in the 90s was not due to better policing strategies or a buoyant economy (they may have made a small difference) but the legalization of abortion two decades earlier. It removed a sizeable population of "would be criminals" and crime nose dived.
To summarize, i find this book excellent and insightful and it shows a world seen not just through the eyes of an Economist but that of a criminologist, a sociologist and above all someone who is free from the shackles of convention.