How are the "old" and the "new" expressed in the field of knowledge and know-how? What did we know yesterday, and what do we know today? What was, yesterday, and what is, today, the mythical part in what we believe we know? And how do we define, in each case, the core of concrete and universally valid knowledges? What rights and duties do we acclaim as human beings, as women, as children, as peoples or nations, and what understanding do we today have of these rights and duties? What is the impact, of what we today call globalisation, on the evolution of knowledge, know-how, and the awareness of such rights and duties? To these questions, and to other related ones, this book provides some answers. It is the result of a conference held in Cotonou in October 2006, on the theme "Traditional knowledges and modern science". It is dedicated to the memory of Georg Elwert, a German Africanist who passed away in 2005, and whose work on Benin, Africa and the Third World remains a source of inspiration for many.