Nikolai Petrovich Likhachev (1862-1936), a well known Russian historian, was a specialist in several auxiliary disciplines, including source studies, Russian diplomatica and sphragistics studying seals attached to documents as a source of historical information. Also available by the author: Diplomatika: Iz Lektsii, Chitannykh v S. Peterburgskom Arkheologicheskom Institute (2001); Manera Pis"ma Andreia Rubleva (2012). (0.905 kg.)