This book contains the works of one of the largest Russian social scientists Vladimir Vasilyevich Krylov (1934-1989) on the theory of socio-economic formations. The first part of the book deals mainly with the sharply debated fundamental questions of the theory's methodology; among them are questions about the historical systems of productive forces in their procedural, structural and other manifestations, about the distinction between economic and non-economic, strong-willed production relations and the differences in the "ownership formula" due to this distinction, about the justification of the typology of pre-capitalist historical systems, about the deployment of the category "capital" in the category "multi-layout" (moreover, in its "split" version), etc.