I read this book about 10 years ago and read it again this summer... Obviously, it has become a timely read in our current climate, and I hope the author writes an addendum addressing recent events. I promise not to get too political, but I do want to set up what is argued and then let any who choose to read it draw their own conclusions. In short, he basically argues that conspiracy theory is a time tested fascinating phenomenon. In an attempt to explain an event that seems to have holes in its narrative and/or lack plausibility and/or proof... people are willing to accept an alternative account with much bigger holes and far less plausibility and almost zero proof. It couldn't have been Oswald acting alone... so it must have been the Russians, The Mob, The Johnson lead Deep State, A New World Order, Unicorns... He talks in detail about how and why this happens... who it appeals to... and its impact. He also argues that, due to man's nature, true successful conspiracies are almost impossible. Man is just too social and egotistical; therefore, most attempted actual conspiracies are leaked or foiled or get exposed. He uses a historical timeline of conspiracy theory from the impact of the publication of The Protocols of the Elders of Zion to more modern examples like the death of Princess Dianna and the 9/11 Truther movement to take the reader on a journey while making his points and arguments. It's a good, but scholarly read. I recommend it... and... if you want to point out to me that 'that's exactly what they want you to think...' you can save it...
You can't spell "conspiracy" without Aaronovitch plus an s and a p and a y, minus an a minus an o minus a v minus a t minus an h.
A similar topic regarding disinformation campaigns that I found interesting... Project Beta : The Story of Paul Bennewitz, National Security, and the Creation of a Modern UFO Myth