This essay traces the modern-day usage and understanding of temples from the Kirtland Temple to Nauvoo and the Salt Lake Temple. Architecture was used to teach principles. While the Kirtland Temple was preparatory (think of the vision of Christ and the conference of keys by Abraham, Moses, Abraham, Elias, and finally Elijah), the Nauvoo Temple was dedicated to ritual usage. In 1879, the Church reduced temple usage to rituals, and thus assembly rooms are missing from later temples. Through his paper, Cowan shows how temples have changed according to revelation and how prophets have seen models in vision that then have been incorporated in the temples God’s people built.