The Voynich Manuscript:
The man is insane who writes a secret in any other way than one which will conceal it from the vulgar and make it intelligible only with difficulty even to scientific men and earnest students.... Certain persons have achieved concealment by means of letters not then used by their own race or others but arbitrarily invented by themselves. - Roger Bacon
Of course, the Voynichese number system must be more complex than the example above. For one thing there doesn't seem to be an obvious marker analogous to `#'. Also, some symbols may occur twice in the same word, and the the eight gallows letters are mutually exclusive. There are also historical/psychological problems with the nomenclator theory: such a system would have been extremely slow to write and read --- why would the author use it to encode a whole book? But who knows...
