The Existence of God is a theological treatise written by François Fénelon, French Catholic archbishop and theologian. The book presents the demonstration of the existence of God, drawn from the knowledge of Nature and proportionate to the feeble intelligence of the simplest.

François Fénelon (1651-1715), was a French Catholic archbishop, theologian, poet and writer. Today, he is remembered mostly as the author of The Adventures of Telemachus and several important theological works. Fénelon defended universal human rights, and the unity of humankind. He also wrote of women's education.