Book excerpt: This book is dedicated to engineers those who work in the field of gear design, gear production and gear application. The following is understood by "engineers" in the wide sense of the word, namely those involved in design, those who have to study machining methods, those who have who are responsible for overseeing gear production processes and gear tooling specialists. In the following pages, some achievements by the authors along with some of old notions have been brought together, that is things which are already known to many readers but that in any case may be useful to "newcomers". There is also some other updated information which may be useful to those who are not new to the trade. This book should in part be informative while at the same time they should also form a kind of pocket handbook.