Preface. The Importance of Distinguishing Between Natural and Other Outbreaks of Disease; G.S. Pearson. Outbreaks of Disease; T. Toth. The Agents of Concern; R. Monteleone-Neto. Natural Outbreaks of Disease: Communicable Disease Surveillance in the Czech Republic; B. Kriz, J. Kyncl. Distinguishing Between Natural Disease Outbreaks and Deliberate Attacks on Human Beings Using Biological Weapons; M.R. Dando, S.M. Whitby. Characteristics of Natural Outbreaks of Crop Diseases; P. Rogers. Distinguishing Natural and Unnatural Outbreaks of Animal Diseases; M. Hugh-Jones. Detecting Anthrax: What We Learned from the 1979 Sverdlovsk Outbreak; J. Guillemin. Scientific Techniques to Distinguish Natural and Other Outbreaks of Disease; B. Steyn. Natural and Other Biological Risks from a Medical Service Perspective; T. Sohns, E.J. Finke. The WHO Role in Surveillance and Control of Emerging Infectious Diseases; R. D'Amelio, et al. Reporting of Outbreaks of Disease Under BTWC Confidence-Building Measures; E. Geissler, J.P. Woodall. Possible Participation of the State Research Centre of Virology and Biotechnology `Vector' in a National and Global Network for Distinguishing Outbreaks; S.V. Netesov, L.S. Sandakhchiev. Scientific and Technical Means of Distinguishing Between Natural and Other Outbreaks of Disease: An Overview of the ARW and a 2000 Postscript; G.S. Pearson. Index.