The Berne Symposium invited leading scientists of risk assessment research with transgenic crops on an international level in order to enhance the discussion regulators and members of the biotech industry. The goal was to determine the status quo and also to make progress in times of a first global spread of transgenes in agrosystems about risk assessment. The dialogue between scientists, regulators and industry representatives also revealed some lacunes of risk assessment research, which will have to be filled in the future: We still lack longterm experience, for which we will have to collect data with scientific precision. The symposium concluded asking for a risk-oriented longterm monitoring system based on critical science and hard data. This volume presents the discussion sessions as well as the scientific contributions and thus mirrors the risk assessment debate, based not on exaggerated negative scenarios but on critical science and hard data.

For centuries, TK has been used almost exclusively by its creators, that is, indigenous and local communities. Access to, use of and handing down of TK has been regulated by local laws, customs and tmditions. Some TK has been freely accessible by all members of an indigenous or local community and has been freely exchanged with other communities; other TK has only been known to particular individuals within these communities such as shamans, and has been handed down only to particular individuals of thc next generation. Over many generations, indigenous and local communities have accumulated a great deal of TK which has generally been adapted, developed and improved by the generations that followed. For a long time, Western anthropologists and other scientists have generally been able to freely access TK and have documented it in their works. Still, this TK was only seldom used outside the indigenous and local communities that created it. More recently, however, Western scientists have become aware that TK is neither outdated nor valueless knowledge, but, instead, 1 can be useful to solve some of the problems facing today's world. Modem science, for example, has shown an increased interest in some fornls ofTK as knowledge that can be used in 4 research and development (R&D) activities and be integrated in modem innovations. This holds especially true for TK regarding genetic resources, which has been integrated in modem 6 phannaceuticals, s agro-chemicals and seed.

The present work is a continuation of the work initiated in Autumn 1991, which resulted in the book, published by Birkhauser Verlag in 1994, entitled: Methods for Risk Assessment of Transgenic Plants. I. Competition, Establishment and Ecosystem Effects. Already when the work on volume 1 started, it was obvious to the authors, that not only the physical establishment of a transgenic plant outside the cultivated area was important for risk assessment, but also the possible gene-transfer from transgenic plants to other plants had to be considered. It was then decided to write a second volume on test methods, as a complement to the first, covering the main topics: Pollination, gene-transfer and population impacts. The main user groups for this volume are scientists and students working with plant population genetics and risk assessment and administrators with responsibility for legislation of transgenic plants. In order to cover such a broad range of topics, specialist knowledge was required. Therefore, colleagues in Denmark and Switzerland, working in these fields in relation to the concerns of using transgenic plants, were asked to participate. The result was a Danish-Swiss cooperation. A list of contributors to the book and their addresses is shown on p. VII. Financial support, which made the work possible, was given by: The National Environmental Research Institute, Denmark, the Federal Office of Environment, Forest and Landscape, Switzerland, the National Forest and Nature Agency, Denmark, the Danish Environmental Protection Agency and the European Commission, DC XI.