Originally published in 1897, The Evolution of the Idea of God is a study of humans' belief in God from primitive tribal religions to what Allen considered the more advanced Christian view.

The main question explored here is "How did we arrive at our knowledge of God?" Rather than trying to prove or disprove any claims about the divine, Allen's method simply traces the psychological processes that led humans to religious belief, and further, from a belief in polytheism to monotheism. Students of religion, mythology, and human psychology will find this an intriguing work.

Canadian writer GRANT ALLEN (1848-1899) attended university in the United Kingdom and taught at Queen's College in Jamaica. His many published books include mainly scientific books and popular novels, and in 1895 he published one of the first Canadian science fiction books, The British Barbarians.