This volume had its origin in a request by the “Sciences en Questions” Work Group founded at the Institut National de la Recherche Agronomique (INRA) in 1994. I was asked to write it by Dr. Paul Robin on behalf of the group. I would like to thank both Dr. Robin as well as the other members of the group for giving me this opportunity. Moreover, Dr. Raphael Larrère pored over both the English and French versions, suggesting numerous improvements. His commentaries helped to strengthen the manuscript. In addition, a small grant from the Fondation Agropolis allowed me to spend three enjoyable months in Montpellier, France, where, among other things, I put the finishing touches on this manuscript. Furthermore, I would like to thank the anonymous reviewers of the English language edition as well as Dr. Geof Bowker, who read and commented on the introduction to the English language edition, and Katie Helke of the MIT Press, who shepherded the manuscript through the review process. Note that any texts not available in English were translated from the original French by me. Of course, I take full responsibility for any errors of omission or commission herein.