The author compares various interpretations of the concept of historiographical source and reveals factors that influenced the positions of scholars. It is shown that as far as this key historiographical concept is concerned Russian historiographical tradition could claim continuity since the early 20th to the 21st century. The article demonstrates how various interpretations of this concept influence the quality of contemporary dissertations. The author argues that the ideas of A.S. Lappo-Danilevsky could be used to help compensate for the shortcomings of the existing discourse.