The recent and very useful edition of Rosa Luxemburg’s economic works compiled by Peter Hudis ( The Complete Works of Rosa Luxemburg) left out one essay: her review of the first volume of Karl Marx’s Theories of Surplus Value, edited by Karl Kautsky in 1905. While book reviews are nowadays a minor genre usually limited to a short length, that was not the case when Luxemburg wrote her essay: her review – published in Vorwärts, the daily of the Social Democratic Party of Germany (SPD), just before the outbreak of the Russian Revolution of 1905 – was extensive and dealt with a variety of theoretical and political issues. We offer the first critical edition in English of this work, setting it against the background of Rosa Luxemburg’s previous works and of the revisionist controversy within the SPD and the Second International, as well as contextualizing it within the framework of contemporary polemics with bourgeois economics, particularly with the German historical school and with marginalism. We also offer a comparison between the methodological issues raised by Luxemburg in her review and those raised by Rudolf Hilferding in his review of the third and last volume of Marx’s Theories of Surplus Value, published in 1911. We close with a brief assessment of the place of Luxemburg’s essay in the later development of her economic thought, concluding with The Accumulation of Capital, published in 1913.