Too often technology is seen as inferior to science, as a simple practical application of a self-sufficient "pure" knowledge. Such a dichotomy is for sure an illusion. The contributions met in this volume, reflecting the richness and the density of the session Science, Technology and Industry during the XXth International Congress of History of Science in Liege in 1997, show all technology as nothing less than the bridge between science on one side, society and economy on the other side. And this bridge is not a one-way road but a place of interactions between the theoretical and the applied, between the knowledge and the know-how. A special section of this book demonstrates that this equal footing dialogue has been particularly intense as far as the military technical development is concerned, and that for many centuries.