Most religious organizations that appear in fiction have no say in how they get written. Dion Fortune had every say. The founder of the Society of the Inner Light wrote The Sea Priestess in 1935 and the book's own copyright page did not read her name alone. It read "Copyright 1935 Society of the Inner Light," the organization itself, not its founder personally, holding the rights to a novel about a mysterious priestess and the man drawn into her orbit of tidal, lunar magic.
That is not incidental. Fortune had already written The Mystical Qabalah, her expository textbook laying out the Society's Western Mystery Tradition system in prose designed to instruct. The Sea Priestess was, by the Society's own account on its current website, a second attempt at the same material: "an attempt to give practical exemplification to the theoretical principles" of that textbook, teaching by narrative what the nonfiction had taught by argument. A reader who wanted the doctrine could go to the textbook. A reader who wanted to feel what the doctrine claimed to describe, ritual as lived experience rather than instruction, could go to the novel instead.
This is the rare case in a survey of media representation where holds is not a stretch. The work was not produced about the Society by an outsider, sympathetic or otherwise; it was produced by the Society, through its own founder, under its own copyright, and its own current website still frames the book the same way nearly a century later. Where most entries in this survey ask how an order looks from outside, this one is a rare chance to see how the order chose, deliberately, to look from within, and to keep looking that way for as long as it has existed.