Trained as an architect, Timothy Wyllie (1940-2017) was a graphic artist and writer who, after a near-death experience in 1973, specialized in the study of nonhuman intelligences, such as angels, ETs, and dolphins. He was the author of 13 books, 7 of which are in this Rebel Angels series, including The Return of the Rebel Angels and Awakening of the Watchers.
https://www.timothywyllie.com/
https://www.innertraditions.com/author/timothy-wyllie
https://www.simonandschuster.com/authors/410050391
https://www.amazon.com/stores/author/B001K7NLFS/