. . . relationship between Stalinism and Leninism. We are here faced not with two clearly definable categories, between which a systematic opposition may be established, but with a complex of inter-related and mutually conditioning problems, which resist simplistic attempts to draw precise lines of demarcation. The fact that Leninism was transmitted and consolidated through the mediation of Stalinism is not something that can be erased by a simple sponge-stroke of intellectual reasoning. Even when it is thought to have been refuted and discarded, this ‘mediation’ continues to operate indirectly in mental categories and structures which have taken such deep root in habits of thought that it is often not possible to recognize their origin. For this reason, the method of exploratory soundings seemed preferable to more ambitious, but perhaps still premature endeavours; their function is to prepare the ground for the recomposition of a homogeneous conceptual apparatus lacking in contemporary Marxism.