This history of the German-Dutch communist left goes against the stream of present-day historiography. It does not aim to be a purely social history of this current. It aims to be a political history, restoring life and relevance to all the political and theoretical debates which developed within it. It aims to place this left in its international context, because otherwise its existence becomes incomprehensible. It aims above all to be a critical history, to show, without a priori assumptions or anathemas, its strengths and its weaknesses. It is neither an apology for nor a rejection of the German-Dutch communist current. It aims to show the roots of the councilist current, the better to underline its intrinsic weaknesses and explain the reasons for its disappearance. It also aims to show that the ideology of councilism expresses a movement away from the conceptions of revolutionary marxism, which were expressed in the 1930s by the Italian Left and the KAPD. And as such this ideology, close to anarchism, can be particularly pernicious for the future revolutionary movement, because of its rejection of the revolutionary organization and of the Russian revolution, and finally because of its rejection of the whole experience acquired by the past workers' and revolutionary movement. It is an ideology which disarms the revolutionary class and its organizations.