The book was published on the occasion of the 100th anniversary of the birthday of Helmut Grunsky. It gives evidence of the scientific activity of an outstanding German mathematician in the period 1930-1983. Two interesting articles complete the picture of the personality of H. Grunsky. The first one, written by Ch. Pommerenke, gives a survey of the Grunsky contribution to function theory, which was his main field of research (Grunsky dedicated 35 of the 45 articles to various topics on this theory). The second one, written by R. Siegmund-Schultze, describes a part of the Grunsky biography on the background of the political climate during the nazi regime. In addition to very profound results on function theory, the reader can find papers discussing some generalizations of the usual diffusion model and interesting survey papers on new results in the theory of Riemann surfaces (1959) and on the main notions in analysis from the point of view of their historical development (1960).