Theorien über den Mehrwert
In his preface (dated 5 May 1885) to his edition of Volume II of "Das Kapital" and in several letters during the following ten years, Friedrich Engels had indicated his intention to publish the manuscript of "Theories of Surplus Value", which was to form Volume IV. However, although he succeeded in publishing the second and third volume of "Das Kapital", Engels was unable to publish the "Theories" before he died in 1895.