Two locations frame Fortune's mature work: Glastonbury Tor and a Sunday letter. Avalon of the Heart, her love letter to Glastonbury, records the pull the place exercised on her from the early 1920s, when she established a hostel and sanctuary at the foot of the Tor; she read the landscape as a meeting of currents Christian, Arthurian and elemental, and her community kept the site as a place of retreat and vision work.
The Society of the Inner Light, the order she founded in London, alternated between the two poles, temple work in Bayswater and the green mysteries of Somerset. When the war came, she turned the society's method to national defence. From October 1939 into 1942 she circulated weekly letters to members scattered by the emergency, setting a common meditation for a fixed hour each Sunday: visualisations of angelic patrols along the coasts, of the rose upon the cross, of Arthur and the company of Avalon standing guard over Britain.
The letters, later published as The Magical Battle of Britain, are the fullest surviving record of an occult order operating as a civilian morale institution, and they are strikingly practical documents, concerned with fear, fatigue and continuity of work under bombing; her own house was damaged in the Blitz. She did not live long past the emergency, dying in 1946, and her society continues, but the wartime letters remain the clearest window into what she thought trained imagination was actually for.