Knowledge Management is a broad, critical and strategic issue for all the companies. The key to competitiveness is knowledge, because of the necessity of reactivity, flexibility, agility and innovation capacities. Knowledge itself is difficult to measure, but what is visible is the way of improving products, technologies and business. Over the last four years, based on the experience of many leading experts around the World, CIRP has decided to prepare and structure a Network of Excellence (NoE) proposal. The European Community agreed to found it and this NoE aim was to build a "Knowledge Community in Production ". This was possible because the partners were representative of the most important universities in Europe and because of strong partnerships with laboratories far from Europe (Japan, Australia, South Africa, the USA, etc...). This book helps to understand what knowledge is and why it is one of the most strategic issues of future manufacturing competitiveness, mainly based on high level technologies and very innovative products. The collective experience that contributed to the publication of this book is unique because it is based on 34 contributions, very complementary, very representative of the current state of affairs and topical issues in Knowledge Management. The fundamental Knowledge Management concepts, methods and tools are described. Concrete experiences are explained and discussed. The specific context and some cases in European level manufacturing knowledge sharing constitute a very original added value of this book