This dissertation advances the Doctrine of the Subtle Worlds, which holds that the physical world is a small cross-section of the real world, and that the real world is composed of several different, separate but partially overlapping realms of being, each with its own unique characteristics, and each inhabited by various beings such as angels, demons, and disincarnate human beings. This Doctrine was held by all premodern civilizations, and has, in modern times, been advanced in Theosophy and in the cosmology of Sri Aurobindo. This dissertation introduces the doctrine, explores its presentation in Sri Aurobindo, and then uses elements of Alfred North Whitehead’s philosophy of science and elements of his later metaphysical scheme to first outline Whitehead’s revolutionary understanding of time, space and matter, and then, in terms of that understanding, to demonstrate a meaningful relationship between the Doctrine of the Subtle Worlds and the world as it is understood by modern science.