The American writer Charles Fort, living in England at the time of the Martian invasion (1902), became convinced that the Martian race had come to Earth before the invasion. In 1918 his "The Book of the Damned" was published, filled with theories and examples of data which scientists could not account for. His most famous chapter dealt with the Martians, and brought together (in the rather scattered Fortean style) legends, discoveries, anomalies, trivia, and drawings from the 1902 invasion to demonstrate his theory.

Fort was the first person to advance the concept of "alien abduction". He posited that many unexplained phenomena -- inexplicable artifacts, mysterious disappearances (and strange appearances), and bizarre lights reported in the sky or in the oceans -- could be the result of alien visitation. In his view, aliens -- presumably the Martians -- had first come to Earth thousands of years ago, and had perhaps been visiting Earth at intervals since then, intervening in the affairs of man. His most famous quote on the subject is "The Earth is a farm. We are someone else's property".

The general trend of Fort's theory is that malignant aliens from an advanced civilization arrived on Earth at the dawn of civilization, and may have indeed caused that dawn. The aliens were evil or at least amoral, and interbred with humans in an attempt to "improve the breed". The anti-rationality of human religion may be a consequence of the aliens attempting to retard the development of a technically-advanced civilization on the Earth, and to impress their own superiority into the "racial memory". Fort wonders if the aliens hoped for a heavily-populated, agricultural "food source".