Note from the author
In May 1970, upon the occasion of the 150th anniversary of the birth of Friedrich Engels, the town of Wuppertal had organised an international scientific conference. This occasion brought together around 50 specialists from more than 10 European countries, as well as Israel and the United States whose task was to take stock of modern research on the thought of he who is universally taken to be, alongside his friend Karl Marx, one of the founders of “Marxism”.