Some writers seem to crave anonymity. None more so than the author of the Voynich manuscript, who invented a mysterious language and an unknown alphabet that has been defying scholars for 500 years.

To judge from the illustrations, the text deals with astronomy, biology, cosmology, herbs, and recipes. Handwriting experts say that the glyphs were written with speed and care, as if the author were facile with them. Statistical analysis seems to show that it’s a natural language, but the vocabulary is unusually small, and in some ways it seems to resemble Arabic more than European languages.

Because no one knows precisely what the 240-page book is, it’s hard to guess who wrote it. Suspects include a who’s who of Europe in the Middle Ages, Roger Bacon and John Dee among them. The cipher has resisted even the National Security Agency, leading some to think it’s a hoax, but even that is hard to prove conclusively.

There’s a great irony at the bottom of this. The mysterious author was one of the most successful cryptologists in history — so successful, in fact, that we may never know who he was.