Transgenic mice have become of central importance for basic biological research, and for understanding diseases involving malfunction of the genetic machinery. The value of these animals as research tools may extend far beyond the purposes of the research project for which they were generated. Their documentation and conservation -- as live animals, embryos or gametes (eggs or sperm) -- therefore becomes of high importance. This proceedings brings together scientific papers covering the breadth and significance of model animals used in scientific research, and scientific and policy summaries based on workshop discussions.