Hyphenation has generally been standardized. However, when a word appears hyphenated and unhyphenated an equal number of times, both versions have been retained (offhand/off-hand).
"Etude/Étude" and "etude/étude" are used interchangeably. This has been retained.
Discrepancies between the Table of Contents and individual chapter headings have been retained. Page references have been corrected.