In his retirement, Dowding became actively interested in Spiritualism, both as a writer and speaker. His first book on the subject, "Many Mansions", was written in 1943, followed by "Lychgate" (1945), "The Dark Star" and "God's Magic". Rejecting conventional Christianity, he joined the Theosophical Society which advocated belief in reincarnation. He wrote of meeting dead "RAF boys" in his sleep – spirits who flew fighters from mountain-top runways made of light. The American poet H.D. fictionalised her early involvement with Dowding and Spiritualism in her novel "Majic Ring", written in 1943-4 but not published until 2009.