Christopher Knight is the author of several books dealing with psychological conspiracy theories such as 366 Degrees of Geometry and the Origins of Freemasonry. Knight appeared in the History Channel's two-part documentary Decoding the Past - "Mysteries of the Freemasons." In an interview about the book Who Build the Moon?: 2005, Knight stated that the Moon is an artificial structure that may have been built by humans with a message in the "base ten arithmetic so it appears as if it is addressed to the ten-number types living on Earth at the present time - which He seems to mean humans." He believes that it was created to make life on Earth possible, including humans, and that the builders were most likely future humans using time travel.