Any initial doubts I had that David Aaronovitch could live up to his weighty subtitle – "How conspiracy theory has shaped modern history" – were dispelled pretty early on in this exhaustive but fascinating account of the major conspiracy theories of the past 100 years. He includes the ones that we might expect – from Oliver Stone's rubbishing of the Warren Commission's report on the assassination of JFK, to Mohammed al-Fayed's theory that MI5 and Prince Philip played a part in the car crash that killed his son and Princess Diana. But Aaronovitch also takes on those other inflammatory theories that have shaped society's attitudes towards certain groups and which, he argues, have caused them great harm.
His first case is the 1919 English-language publication of the Protocols of the Elders of Zion, a book purporting to be a secret manifesto for Jews, instructing them how to take over the world. What is shocking is how seriously this book was regarded.
In the case of Pearl Harbor, respected journalists and political opponents were ready to believe, and to propagate the message, that Roosevelt had let Japan bomb the Hawaiian airbase deliberately, as an excuse to enter the war – just as some believe that 9/11 was brought about by the US government.
Conspiracy theories are not mere silly little stories invented by a few sad individuals, Aaronovitch shows. They pander to society's worst prejudices. They lie at the heart of a certain distrust we have, as well as the "compulsion to create a story" and a propensity for "hysteria", such as that characterised by the national reaction to Diana's death. Far from showing brave individuals fighting totalitarian states, conspiracy theories paint people at their least rational, their most reactionary and, sometimes, their most murderous.