Cryptomenysis Patefacta: Or the Art of Secret Information Disclosed without a Key. Containing, Plain and Demonstrative rules, for Decyphering all Manner of Secret Writing. With Exact Methods, for Resolving Secret Intimations by Signs or Gestures, or in Speech. As also an Inquiry into the Secret ways of Conveying Written Messages: And the several Mysterious Proposals for Secret Information, mentioned by Trithemius, &c - John Falconer 1685 - Daniel Brown, London - First Edition A complete first edition of this scarce work on cryptography, the second to be published on the subject but the first of practical value, according to Kahn (The Code Breakers) ‘Up until Falconer the literature was all theory and no practice’.

‘Falconer also gave what seems to be the earliest illustration of keyed columnar transposition, a cipher that is today the primary and most widely used transposition cipher, having served (with modifications) for French military ciphers, Japanese diplomatic superencipherments, and Soviet spy ciphers.’ – Leeuw,
The History of Information Security.

‘“The second English book on the subject excelled”, according to David Kahn (
The Code Breakers), and its high quality is all the more surprising when one considers that John Falconer had written Cryptomenysis Patefacta in France some thirty years before its first publication in 1685 while serving the Duke of York, the future King James II, during his period of exile there (1652-1660). Falconer about whose life little is known except that he apparently was entrusted with the Duke’s private cipher until he died in France, was a master of the trade. He structured his book in five sections, dealing with the ways of “Secrecy in Writing”, such as cryptography, steganography, and simple “Rules for Decyphering them without a key”; of the “Methods of Secret Information, by Signs and Gestures”; by the “Secrecy consisting in Speech”; “Of Secret Means of Conveying Written Messages”; and lastly, with “the several astonishing Proposals for Secret Information... concerning [Trithemius’] eight Books of Steganography”. Falconer’s sources are limited; they include Trithemius, Machiavelli, Kaspar Schott, Francis Bacon and Bishop Wilkins, but they suffice to provide a solid overview, which includes “the earliest illustration of keyed columnar transposition, a cipher that is today the primary and most widely used transposition cipher” [Kahn].’ - Leeuw & Bergstra, The History of Information Security.
  References: Gibson 387. Wing F296. Leeuw & Bergstra, The History of Information Security 303. Kahn, The Code Breakers 156.

Small Octavo (17.1 x 11 cm) pp. [4 (additional free endpapers)] [2][1 (Title)] [1] [6 (Epistle Dedicatory)] [4 (To the Reader)] [2] [9 (Introduction)] [1] 180 [2] [2 (additional free endpapers)]. A-N8 (A1, A8, N8 blanks).
  Bound in full brown contemporary sheep, rebacked to style in smooth calf, spine in six compartments, panels with single filet border in blind. contemporary sheep, rebacked   Condition: Near fine, some soiling to endpapers, some toning to pages, in very good binding with wear to corners and edges.   Ref: 108839   Price: HK$ 34,000