Modern surgical oncology is characterized by multimodal therapy. In recent years numerous therapeutic approaches of pre-, peri-, intra-and postoperative treatment have been in­ vestigated with regard to their use in combination with surgi­ cal intervention. It now is time to analyze and to define the state of our knowledge. For tumors of the gastrointestinal tract there are several encouraging therapeutic approaches, such as preop­ erative chemotherapy in esophageal and perioperative chemotherapy in colon cancer. For some special tumors, like anal carcinoma, we have clearly defined combined therapies which even now must be viewed as standard treatment. It is also time to demonstrate the results of several clini­ cal studies that have been conducted within the last few years that combined surgical efforts with pre- or postinter­ ventional chemotherapy or radiotherapy. It is necessary to evaluate whether these trials contribute to progress in onco­ logical therapy. The editors of this volume - surgeons at the university hospitals of Heidelberg and Zurich - must be given the mer­ it of achieving these goals. It was especially appropriate for the Department of Surgery in Heidelberg, in close cooperation with the Comprehensive Cancer Center Heidelberg/ Mannheim, to prepare a review of our present knowledge of surgical oncology as it is in the tradition of attempting to combine different therapeutic approaches to cancer therapy.