Trithemius wrote a second, related work, Steganographia, which he chose not to publish, circulating it only in manuscript among a small circle of correspondents, and its reputation suffered accordingly: rumors that it taught genuine demonic communication attached to it for over a century, and it was formally placed on the Catholic Church's Index of Forbidden Books in 1609, decades after Trithemius's own death. Polygraphia, by contrast, Trithemius published openly in 1518, dedicated to a reigning Holy Roman Emperor, and its more overtly angelic and planetary framing, closer to the conventions of Renaissance natural magic that educated readers already found intellectually respectable, let it escape the suspicion that dogged its unpublished sibling.
That difference in reception outlasted both books' authors by centuries. Steganographia's true cryptographic content was not conclusively demonstrated until the cryptographer Jim Reeds published a decipherment of its most notorious passages in 1998, showing that what had read for four hundred years as literal instructions for commanding spirits was, in fact, an elaborate coded cipher manual, vindicating Trithemius against the demonic reputation his unpublished work had carried since the sixteenth century. Polygraphia, having always been readable as a legitimate work of learned angelology by those who did not look further, never generated the same controversy, and stands today as the more historically secure of the two: openly printed, correctly credited in its own time as an innovation in secret writing by later cryptographic scholars, and free of the centuries of suspicion its companion book only recently shed.