James Redfield was already developing this hypothesis in his earlier works, such as the Celestine Vision, where he wrote, “Our overriding purpose has been to raise our energy level to the point where we can walk into the Afterlife dimension, essentially merging the two dimensions into one.” His allegorical work ‘The Secret of Shambhala’, has the lead character utter the words, “The Tibetans believe that there is another, more spiritual reality beyond the physical worlds we can see, and that Shambhala, while here on this Earth, lies in the spiritual realm.”
Brian Greene, the foremost modern writer on physics and science, has written in detail about the ‘Hidden World,’ and String Theory predicts that there are at least ten more dimensions in addition to the one we live in. Those who struggle in believing in the ‘spirit world’ proposed by religions, might instead accept the idea of ‘dimensions’ as posited by some quantum physicists. It’s all in the terminology, and the concept of dimensions does in fact account for a range of phenomena such as ghosts, angels, OOBE and some UFO sightings.