Construction chemicals and in particular concrete admixtures, as a major part, represent a complex and multidisciplinary field of technologies. It is therefore not a surprise that there are difficulties to gain an understanding of such complex areas which include chemistry, physics, material sciences, engineering and construction techniques. This book is an attempt to bridge over the different views and languages of chemists, engineers, contractors, concrete technologists as well as environmental specialist. This is a very ambitious target. The lack of systematic teaching at universities was the motivation for the authors to create a handbook which should help students, chemists and engineers as well as any other interested parties to understand admixtures in their variety, nature, mode of action and its performances. The objective was not to deal with scientific details or report on the latest research but even more to give an overview and to show performance characteristics and correlations. This book should also help to promote admixtures as a very useful tool to save resources (eg: water, energy, by improving performances, quality and service life of concrete constructions).