Johannes Trithemius. Polygraphiae libri sex...Accessit clavis polygraphiae liber unus, eodem authore (Six Books on "Many Forms of Writing" [i.e. cryptography], to which is added A Book of the Key to "Many Forms of Writing").
Cologne: Ioannes Birckmannus & Theodorus Baumius, 1571.

8vo.  554 + [52] pages.  154 x 101 mm. Parchment binding.

Trithemius’ Polygraphia is a much more straightforward exposition of cryptography, and lacks the magical trappings of the Steganographia. Finished in1508, it was printed shortly after Trithemius’ death, almost a century before the more arcane companion work. In the preface, Trithemius traces the history of polygraphy from its origins in ancient Egypt through Greek and Roman times and into the Christian era. He notes the particular skill shown by the Franks, and particularly Charlemagne, in acquiring cryptographic skill. He urges Emperor Maximilian, to whom the work is dedicated, to follow Charlemagne’s example. Recognizing that the emperor has other duties, Trithemius concludes by noting that he has appended a polygraphic key to make the techniques more readily apparent.

Most of the book consists of lists of code letters and their equivalents. The page shown here, however, depicts the “code” (more properly, a form of shorthand) Trithemius attributes to Cicero.