Contributors to the work include Thom Burnett, Nigel Cawthorne, Richard Emerson, Mick Farren, Alex Games, John Gill, Sandy Gort, Rod Green, Emma Hooley, Esther Selsdon, and Kenn Thomas.

[7] "Perhaps the conspiracy world is an updated version of ancient myths, where monsters and the gods of Olympus and Valhalla have been replaced by aliens and the Illuminati of Washington and Buckingham Palace," writes Burnett.

[1][10] The encyclopedia has a section on assassinations, and those discussed include the deaths of Kenneth Bigley in 2004, Danny Casolaro in 1991, John F. Kennedy in 1963, and Tutankhamun in 1323 BC.

[12] In a review of the encyclopedia for The Guardian, Andrew Mueller called it a "beautifully-produced tome" and commented that the work "succeeds, as was probably intentional, in offering some fascinating tours of the byways of history and providing a tantalising alternative universe in which much of what you know may not be what it seems".

[1] John Cooper reviewed the encyclopedia for The Times, and described it as "an entertaining compilation of ideas ranging from who was the 'real William Shakespeare' to the BCCI case and al-Qaeda".

[2] Writing in Conspiracy Theories & Secret Societies For Dummies, authors Christopher Hodapp and Alice Von Kannon comment that Burnett asserts "the spirit of our times has had the crap kicked out of it by global domination".