The idea for this book grew out of a NATO Advanced Research Workshop held at the Catholic University at Leuven, Belgium. We are grateful to NATO for support in conducting this workshop and for support in the preparation of this book. We are particularly grateful for their emphasis on designing the workshop to build collegiality. They suggested that we hold the meeting in a small town and that we organize evening activities to keep the group together and to promote informal and extended discussions. What sage advice. The excitement grew over the three days as we shared understandings and enriched our perspectives. Indeed, there was even a proclaimed "near" conversion to a constructivist perspective from one colleague trained in traditional instructional design methods. While we report this as a bit of a humorous anecdote, it most clearly reflects the sense of excitement that developed. We would also like to thank the staff at the Catholic University for their great support during the workshop. Their efforts and their good cheer were important components in the success of the meeting. In particular we would like to thank Jan Elen, Catherine Vermunicht and Jef Vanden Branden. Finally we would like to thank the personnel at Indiana University for their help in assembling this book. Deborah Shaw prepared the index. We thank her for the skill and speed with which she was able to work.