Abstract
Diversity of trajectories of post-socialist transforming economies is a stylized fact of this experience of system change. The paper explores the relations between change in formal and informal rules in historical perspective, discussing new institutional views about rationality of formal institutions and detrimental inertia of informal institutions. It submits that an open and complex approach of the centrality of formal/informal rules interaction may give a better explanation to the multiplicity of national post-socialist pathways.