The conference is now over and enough time has passed for us to realize that the concensus of opinion of the participants is that it was indeed a successful and fruitful conference. This conference showed just how wide spread are the ideas of Otto Toeplitz, and how strong an influence his work has. The majority of participants contributed papers for this volume, which will help to bring to this interesting conference a wider audience. About the background and organization of the conference, the reader can learn from the opening address, which is included in place of an introduction. In my opinion this volume would be of interest to a wide public; experts in pure and applied mathematics as well as persons interested in the history of mathematics. The papers are divided into two sections. The first section is given to research papers, and the second to memorial papers. We are indebted to Professor G. K8the who allowed us to publish in the section of memorial papers the translation into English of his talk, given at a Colloquium in honour of Otto Toeplitz in Bonn. During the preparation of this volume great assistance was extended to us by Dr. Uri Toeplitz and Mrs. G. Riesel to whom I would like to express my sincere gratitude. I would like to take this opportunity to thank all persons and organizations who helped to make this conference such a success, and also Birkhauser Verlag for publishing this volume of the Proceedings.