The authors of the first edition of Lost Envoy were unable to determine a single source from which Spare drew his Minor Arcana card meanings. To our delight, in March 2022 American oracle-card scholar John Choma identified this missing publication, 'How to Tell Fortunes by The Cards', by Rapoza (1906).
This extremely rare cartomancy manual is reverse-bound alongside a facsimile of 'The Tarot', by S. L. MacGregor Mathers (1888), the source from which Spare assigned his Major Arcana card meanings. Both books are introduced by John Choma.