I guess we have all experienced a moment when someone you thought was quite a rational and sensible person suddenly espouses belief in a conspiracy theory, It might be about the 1969 moon landings or the events of 9/11 or global warming being a myth but whatever it is it nearly always implausible. If you point out the holes and impracticalities and the lack of cui bono in these theories you will often find yourself derided as being "close-minded" at best and "brain-washed" at worst. You may begin to wonder, what is it that makes otherwise sensible, educated people believe in the most ridiculous absurdities. If so, this book is for you.

Aaronovitch does a great job of dissecting a whole range of conspiracy theories. He doesn't focus just on evidence-based scepticism to break the theories apart but also spends a considerable amount of time looking into how and why conspiracy theories arise. I felt that this was far more interesting in dismissing the theories themselves. It is pretty easy to disprove most conspiracy theories because they rely on flimsy or twisted evidence, assumptions and vague feelings of how things "might have happened" - it has always seemed to me that people believe in these theories simply because they make sense to them personally. Often people will endorse one fanciful theory whilst dismissing others as crack-pot. What makes people have the ability to think rationally about one set of theories yet buy whole-heartedly into others? Aaronovitch tackles this very question quite thoroughly.

The question is, does it matter if people believe in easily falsifiable untruths? Do conspiracies have an effect on politics? Aaronovitch says yes. Specificially, he says "the belief in conspiracy theories is harmful in itself. It distorts our view of history and therefore of the present and - if widespread enough - leads to disastrous decisions." This is the core of the book and is argued very well.

The only place where the book falls down is in the conclusion. In attempting to pin down why people become so attached to conspiracy theories Aaronovitch dismisses the idea that sometimes a theory may represent a distrust of authority that is not entirely misplaced. There is a theory that the American government weakened levees in predominantly black areas before Hurricane Katrina hit New Orleans. Such a conspiracy would have to include people in local, state and federal government - all of whom supposedly would be rabid racists with no conscious. Yet, it is interesting to look at why such a theory should come about. The American south does have a horrible history of racist oppression that has not entirely disappeared and institutional racism is still rife the world over. Therefore it does make some sense that there is a mistrust of officials would play a part in forming such conspiracy theories. Aaronovitch seems to dismiss this possibility and therefore almost comes across as dismissing racism itself as a conspiracy theory! I feel sure that this is not exactly what he meant but I felt that this angle deserved a deeper analysis than Aaronovitch gave it. Many other conspiracy theories are linked to a deep distrust of those in authority - sometimes with merit and sometimes not. I think another chapter (or even a book!) could be written on how we could distinguish between when a distrust has basis in reality and when it does not.

I would recommend this book to anyone who is on the side of rationality and reality. It is not a difficult read and Aaronovitch is very entertaining. The only thing that this book does not provide is a deeper analysis of the underlying emotions running through society that lead to such theories being formed. However, in term of factual and historical analysis this book is informative and a breath of fresh air.