The idea arrives in its modern form with the Theosophical Society. Helena Blavatsky described a brotherhood of adepts, living men of extraordinary attainment resident in Tibet and elsewhere, and named two of them, Koot Hoomi and Morya, as her own teachers. Between 1880 and 1884 letters attributed to these adepts reached the Theosophist A. P. Sinnett, sometimes appearing in a cabinet or falling from the ceiling, and they contain a good deal of the doctrine that later Theosophy rests on.
The Society for Psychical Research sent Richard Hodgson to India to investigate, and his report of 1885 concluded that the phenomena were produced by Blavatsky and confederates and that the letters were her own work. The report was widely accepted and remains the standard sceptical account.
It has also been contested from within the same society. In the 1980s and 1990s Vernon Harrison, a document examiner and a member of the Society for Psychical Research, published a detailed criticism arguing that Hodgson had worked selectively, that his handwriting analysis did not meet the standards of the discipline, and that the letters are not simply Blavatsky writing in disguise. The Society printed both. The atlas records the dispute as a live one rather than treating either report as final, and notes that neither report establishes that the adepts existed.