This guidebook to mathematics contains, in handbook form, the fundamental working knowledge of mathematics that is needed as an everyday guide for working scientists, engineers, and students. Easy to understand, and convenient to use, this guidebook provides the information necessary to evaluate most problems which occur in concrete applications. This fourth edition has been fully revised and now contains a new emphasis on those fields of mathematics that have become more important for the formulation and modeling of technical and natural processes, namely Numerical Mathematics, Probability Theory and Statistics, as well as Information Processing.