The translation has been kept as close to the original language as possible. Specialist terms and expressions have been retained whenever such terms and expressions exist in the English language. Where this has not been possible, a substitute term with the closest possible meaning has been chosen and an explanation given in the text.
The original notes appear as in the original, as footnotes at the bottom of the page. Other short notes in brackets appear as in the original. Original references are marked with superscript numbers, and the references themselves are placed at the end of the text.
The translator's notes are of two types: short notes included in the text in brackets and in italic (translator's note), and normal notes which are marked by italic numbers in square brackets, [1].
An appendix and a bibliography has been added as an aid to placing this account in its cryptological context and as an incentive to further study.