In 1992, a group of scientists including molecular biologists, microbiologists, population biolo- gists, ecologists, human geneticists, moral philosophers and others met discussing the state of affairs regarding the deliberate or unintentional release of genetically modified organisms. The proceedings of this meeting were subsequently published by Birkhauser Verlag as Transgenic Organisms: Risk Assessment of Deliberate Release (K. Wohrmann and J. Tomiuk). Since then we have gained many new insights that are also worthy of discussion. And although other equally important scientific views on the release of genetically modified organisms exist, we have mainly concentrated on aspects of population biology and evolution. The results of a second meeting in 1995 are summarized here. We are grateful to colleagues and friends for their help in the translation, correction and review of the authors' contributions. We especially want to thank Jutta Bachmann, Donna Devine, Diana von Finck, Friedrich Laplace, Volker Loeschcke, Rolf Lorenz, Dave Parker and Trevor Petney. A grant (BMFT N' 0311035) from the Ministerium fUr Forschung und Techlogie der Bundesrepublik Deutschland again made possible the continuation of this cooperative endeavour.