The Voynich manuscript is an illustrated codex hand-written in an unknown writing system.
No one has yet succeeded in deciphering the text, and it has become a famous case in the history of cryptography.
The mystery of the meaning and origin of the manuscript has excited the popular imagination, making the manuscript the subject of novels and speculation.
None of the many hypotheses proposed over the last hundred years has yet been independently verified.
The codicology, or physical characteristics of the manuscript, are studied by various researchers.
The manuscript measures 23.5 by 16.2 by 5 centimetres (9.3 by 6.4 by 2.0 in), with hundreds of vellum pages collected into eighteen quires (units of 25 pages).
The total number of pages is around 240, but the exact number depends on how the manuscript's unusual foldouts are counted.
The quires have been numbered from 1 to 20 in various locations, using numerals consistent with the 1400s, and the top righthand corner of each recto (righthand) page has been numbered from 1 to 116, using numerals of a later date.
From the various numbering gaps in the quires and pages, it seems likely that in the past the manuscript had at least 272 pages in 20 quires, some of which were already missing when Wilfrid Voynich acquired the manuscript in 1912.
There is strong evidence that many of the book's bifolios were reordered at various points in its history, and that the original page order may well have been quite different from what it is today.