The astral is a real and not an imaginary or hypothetical world and is composed of matter in much finer and far more ethereal states than we find it in the Physical World—so ethereal that even in its densest expression, the physical senses are scarcely able to respond to its vibrations. Nevertheless, the astral is a material world which exists above in the sense of being higher in rate of vibration, the next higher octave (a state of matter conditioned by an octave of vibration above the octave within which the Physical World manifests), as well as extending far above and beyond the earth's surface—around and within the Physical World, interpenetrating every atom more completely than the air penetrates every building, receptacle or body, i.e., this finer astral matter penetrates the coarse physical matter. The astral is, therefore, a locality in space in relation to the Physical World and its lower Realms are so physical that under certain conditions of condensation, their inhabitants can be photographed by the ordinary camera, attesting to the reality and the material nature of the substance of that world.
These seven Realms are classified as follows (giving their correspondence to the Worlds of Manifestation)—
The Realm of Reflection (corresponding to the Physical World)
The Ethereal or Etheric Realm (corresponding to the Astral World)
The Realm of the Life-force or Vital Realm (corresponding to the World of the Life-force or Pattern World)
The Desire Realm (corresponding to the Desire World)
The Mental Realm (corresponding to the Mental World)
The Spiritual or Inspirational Realm (corresponding to the Spiritual World)
The Divine of Ecstatic Realm (corresponding to the Divine World).
If we regard the Astral World as the next higher octave above the physical, its seven Realms will correspond to the same Realms or notes of the Physical World, but in a higher octave, hence will have corresponding characteristics.
Since the Astral World as a whole is the World of sensation and desire, all its Realms partake of those characteristics, although greatly enhanced and intensified by the far more ethereal conditions of that World and includes as many states of consciousness, even more than the Physical World, which is entered through the gate of birth, for birth into the Physical World is death to the Astral World, just as death to the Physical World is birth into the Astral World.
Excerpted and edited from Realms of the Living Dead—A Brief Description of Life After Death, Harriette Augusta Curtiss and F. Homer Curtiss, the Curtiss Philosophic Book Company, Washington D. C., 1926