Transcriber’s notes:

In this transcription a black dotted underline indicates ahyperlink to a page, illustration or footnote; hyperlinks are alsomarked by aqua highlighting when the mouse pointer hovers over them.A red dashed underline indicates the presence of a hidden commentthat can be revealed by hovering the mouse pointer over the underlined text. Page numbersare shown in the right margin. Footnotes are located at the end of thebook.

The text contains some typographic characters that might not displaycorrectly with all viewing devices. If some of the characterslook abnormal, first ensure that the device’s character encoding isset to Unicode (UTF-8). The default font might also need to be changedto a Unicode font such as Arial Unicode MS, DejaVu, Segoe UI Symbol orFreeSerif.

Some pages contain alphabet letters displayed in bold sans-seriffont, but some browsers or viewing devices may display them with aserif font.

The following spelling errors have been corrected silently:
pecularities —> peculiarities
indentification —> identification
classfication —> classification.

Inconsistent hyphenation (e.g. fingerprint, finger-print, fingerprint) remains as in the original text, as does the inconsistentuse of em dashes in the index.

A few illustrations have been relocated nearer to the relevant text,and their page references adjusted appropriately in the list ofillustrations.