The present volume contains articles pertaining to a wide variety of sub­ jects such as conformal and quasi conformal mappings and related extremal problems, Riemann surfaces, meromorphic functions, subharmonic
functions, approximation and interpolation, and other questions of complex analysis. These contributions by mathematicians from allover the world express con­ sideration and friendship for Albert Pfluger. They reflect the wide
range of his interests. Albert Pfluger was born on 13 October 1907 in Oensingen (Kanton Solothurn) as the oldest son of a Swiss farmer. After a classical education he studied Mathematics at the ETH-Zurich. Among his teachers
were Hopf, Plancherel, P6lya and Saxer. P6lya was his Ph.D. adviser. After some teaching at high schools (Gymnasien), he became professor at the University of Fribourg, and a few years later (1943) he was appointed as
successor of P6lya at the ETH. He retired in 1978, but has always remained very active in research. Pfluger's lectures were highly appreciated by the students. His vivid and clear teaching stimulated and challenged them to
independent thinking. Many of his Ph.D. students are now themselves teaching in universities. His main research relates to the following fields: entire functions, Riemann surfaces, quasi conformal mappings, schlicht functions.
(See list of publica­ tions.) He collaborated with several mathematical colleagues, in particular with Rolf Nevanlinna, who taught parallel to him at the University of Zurich. In 1973 Pfluger was nominated foreign member of
the Finnish Academy of Sciences.