For a number of years the promise of biotechnology has been dimmed by concerns over the intrinsic safety of transgenic organisms. Although considerable knowledge of the properties of recombinant systems and a vast volume of data gathered from different applications are now available, these concerns are still evident. In the developing world, there are also fears that such countries might be used as testing grounds for recombinant products. Considerations of this nature have often overshadowed the benefits these countries might derive form the application of genetic engineering. In response to these concerns, UNIDO, together with the United Nations Environment Programme and the World Health Organization, formed in 1985 the Informal Working Group on Biosafety. In 1991 the Food and Agriculture Organization of the United Nations also joined the Group. The present volume was commissioned by the group and is intended to help scientists and regulators to conceptualize the major issues underlying biological safety as well as to understand how these affect policies to regulate biotechnology.