The following 167-page publication compiles articles submitted during the Toxin Day Workshop held at the University of Rome, Italy (24 May 2004). Experts on toxinology provided discussions on various aspects of toxin biology, giving integrated views on the role and mode of action of these substances. This book, however, is not limited to workshop proceedings, as the core topics covered at the meeting are complemented by additional contributions by leading scientists in the field of toxin biology. Rearrangement of the scientific material and integration with external updates on recent developments in the field provides the reader with a broader view of both established and emerging aspects of toxin structure, action mechanism and role in disease. Nevertheless, the book does not serve as a comprehensive treatise of toxinology as the discussions focus only on a few prototypic toxins.