In continuation of the Covance Primate Symposium Series, the 15th Covance Primate Symposium was held in Münster during September 2004. The symposium's theme was "New Developments and Challenges in Primate Toxicology" with specific contributions to the topics immunotoxicity testing, reproductive/developmental/juvenile toxicity evaluation, QT prolongation and new trends/techniques/models. There is obviously increased awareness of the advantages and superior relevance of nonhuman primate models for assessing toxicity to specific and selected target organ systems. The advent of biotechnology and the resulting preclinical development of biologics (large molecules, antibodies etc.) with highly confined species specificity frequently render the nonhuman primate the only relevant model available for toxicity studies. Hence, it is pivotal that specialists and experts meet on a regular basis to exchange new ideas, methods and prospects for primate toxicology.This publication represents the 4th book of the Covance Primate Symposium Series.ContributorsAndreas Bauer, Martin Bergmann, Gerd Bode, Roland Brandt, Eberhard Buse, Jeanine L. Bussiere, Joy A. Cavagnaro, Werner Frings, Stefanie Friderichs-Gromoll, Jörg Gromoll, Gunnar Habermann, Joachim Kaspareit, C. Marc Luetjens, David R. Mann, Wolfgang Müller, Marc Niehoff, Kerstin Niggemann, Piotr Nowak, Petra Stute, Gerhard F. Weinbauer, Joachim Wistuba, Karl Zilles, Ulrich Zühlke.