Just read an article about the Voynich manuscript, named after the rare book collector who bought it in 1912. Tests performed on it date it as medieval, and it seems to be split into sections on ‘herbal’, ‘astronomical’, ‘biological’, ‘pharmaceutical’, ‘cosmological’ and ‘recipes’, all written in an indecipherable language and bizarrely illustrated throughout.
This book has been studied by many cryptographers but its meaning and origin remain a mystery. Theories are diverse and include that it is simply hoax, that it is an old European language which has been put through some sort of cipher (such as the Cardan grille), or indeed that it is transcribed Enochian, the so-called language of the angels.

link to the scanned book http://brbl-dl.library.yale.edu/vufind/Record/3519597

more information at world mysteries.com here and here
on ellievelinska.blogspot.co.uk and aartichapati.com

The Voynich Manuscript: The unsolved riddle of an extraordinary book which has defied interpretation for centuries: The Unsolved Riddle of an … Book Which Even Today Defies Interpretation on amazon.co.uk