The definition of the term "pyrolytic carbon" is given. Types of microstructures of pyrolytic carbon and development of their classification are presented. Various structures and modes of occurrence of pyrolytic carbon deposits in relation to the conditions of their formation, in nature as well as final effects or by-products of laboratory and industrial processes, are presented based on the literature and the authors' own research. (C) 2016 Elsevier B.V. All rights reserved.