This book is a translation of the forthcoming fourth edition of our German book /"Funktionentheorie P' (Springer 2005). The translation and the LATEX files have been produced by Dan Fulea. He also made a lot of suggestions for improvement which influenced the English version of the book. It is a pleasure for us to express to him our thanks. We also want to thank our colleagues Diarmuid Crowley, Winfried Kohnen and Jorg Sixt for useful suggestions concerning the translation.