Natural toxins form a major component of the molecular tools used increasingly frequently by the ever growing number of laboratories of various kinds. Evidence for this is provided not only by the increasing number of firms including such toxins in their catalogues but also by the large number of demands received by those who discover new toxins. Twenty chapters survey important aspects of toxin origin, their structure and molecular mechanism, and their cellular and pathogenic effects. In addition, the text provides comprehensive and specific methodology for the application of these toxins in the research laboratory. This begins with the description of the method of extraction, biochemical and pharmacological characterization, and assessment of purity, and continues with methods for chemical modification, e.g. labelling, and eventually describes applications in pharmacological studies in vivo and/or in vitro. The length of this book has been kept reasonable by concentrating on animal toxins, ...