No doubt: A perfect coating has to look brilliant! But other properties of coatings are also most important. Coatings have to be durable, tough and easily applicable. Additives are the key to success in achieving these characteristics, even though the amounts used in coating formulations are small.It is not trivial at all to select the best additives. In practice, many series of tests are often necessary, and the results do not explain, why a certain additive improves the quality of a coating and another one impairs the coating.This book is dedicated to developers and applicants of coatings working in research or production, and it is aimed at providing a manual for their daily work. It will answer the following questions: How do the most important groups of additives act? Which effects can be be achieved by their addition? Scientific theories are linked to practical applications. Emphasis is put on the optical aspects that are most important for the applications in practice. This book is a milestone in quality assurance in the complete field of coatings!