Brian Leftow makes an important contribution to the longstanding debate among philosophers and theologians about the nature of God's eternity. The author develops a powerful and original defense of the notion that God is eternal in that he exists timelessly; that is, that though God exists, he does not exist at any time. Leftow defends the claim that a timeless God can be an object of human experience, and he attempts to delineate the extent of such a God's omniscience. Finally, the author pays special attention to the relation between the claim that God is timeless and the claim that God is metaphysically simple.