Most biographies arrive after their subject's reputation has already settled. June Johns's King of the Witches, published in London in 1969, did the opposite: it appeared while Alex Sanders was still actively building the very reputation the book describes, a self styled king of the witches courting newspapers and television cameras at the same time he was organizing what would become Alexandrian Wicca.
Johns had direct access to Sanders and the people around him, which gives the book a value few later accounts can match: it captures how Sanders presented himself and his movement to the public in real time, not as later historians reconstructed it. That same closeness is also its limit. Sanders was, by every account including sympathetic ones, an accomplished self promoter, and Johns wrote with his cooperation rather than at a critical distance from him.
Read today, the book works best as a period document rather than a settled historical record. Its account of Sanders's own telling of his initiation and the founding of his coven is valuable precisely because it shows what Sanders wanted believed at the time, which is not always the same thing as what later, more independent historians have been able to confirm about Alexandrian Wicca's actual early years.