IN STYLE IT TOOK THE SHAPE of any other garden party, that signal diversion of the interwar years. Tea and jellies, dancing and croquet, "lemon-ade" and clock golf:

Octavia gave a Garden Party to all at the Centre, in the Garden of The Haven, on the 18th — a most perfect day. Tea was served under the big weeping ash-tree named Yggdrasil. After the Meeting, twelve of the party danced country-dances, dressed as country people in smocks and panier dresses.

The only difference being that the dancers thought they were cavorting in the Garden of Eden, reestablished in the market town of Bedford, about 50 miles north of London. And they believed their host was the daughter of God.

Let's back up a bit. More than a hundred years earlier, in the second decade of the 19th century, a domestic-servant-turned-prophet from Devon named Joanna Southcott declared herself the expectant mother of a new female messiah. As Southcott and her followers believed, this child (the half-sister of Jesus) would complete the unfinished project of redeeming mankind from original sin. Southcott died in 1814 without having given birth, but her writings and prophecies — some of which were sealed in a large wooden box, with instructions to be opened by 24 bishops of the Church of England in an unspecified time of "grave national danger" — became the sacred texts of a small but determined 20th-century community that tended garden, as it were, religiously.

In 1919, Mabel Barltrop declared herself the child of Southcott's prophecy, and convened a group of mostly unmarried white upper-middle-class British women to wait out the Second Coming with all the comforts of country life in Bedford. Disaffected by their silencing in the Anglican establishment, Barltrop and her companions fashioned an eclectic millenarian heterodoxy. They drew from Southcott's texts as well as from the pages of popular 19th-century religious movements (including Theosophy, Spiritualism, and Christian Science) to supplement their High Church histories and theological attachments. The community — eventually known as the Panacea Society — offered its followers both spiritual and practical forms of relief. Some left disappointing or abusive marriages for a life of comparatively desirable celibacy; many revalued "spinsterhood" by joining a group of women largely liberated from domestic obligations (though someone always had to serve the tea). They believed in direct communication with God, second baptism, and spiritual healing. They also rode bicycles, went to the movies, and danced in country drag.

The transformation of Barltrop, the self-educated wife of a vicar and mother of four, into Octavia, daughter of God — the charismatic, exacting figure at the center of Jane Shaw's group biography, Octavia, Daughter of God: The Story of a Female Messiah and Her Followers — is a remarkable one. Confined to a mental hospital for "nervousness" after the death of her husband, and suffering from what Shaw reads convincingly as a form of OCD, Barltrop found both consolation and community in Southcott's writings. For Southcott had set forth a decidedly female-centered theology: woman, responsible for the world's fall, would in turn be responsible for its restoration. Furthermore, the upheavals of the Great War — by a...