The foreword is followed by a few further remarks on the background and motivation for this book project and an introduction to the man and political economist Eugen Varga. This is continued and deepened by a brief excursus on Varga’s early work for the Communist International (CI). The excursus explains and illustrates some of the problems and contradictions with which Varga was confronted; it is intended to help in developing an adequate understanding of his scientific and political search processes. A note on the handling of Varga’s written legacy leads to some remarks on Varga’s relationship with Rosa Luxemburg. On the one hand, this has to do with the editors’ central thesis of the contradictory reception and continuation of the Karl Marx/Friedrich Engels-Rosa Luxemburg thread by Eugen Varga. On the other hand, the literature contains controversial accounts of Varga’s scientific and political relationship with Rosa Luxemburg which require some response.