The relevance of the publication is related to the fact that in Russia, 2019 was declared the year of the writer Daniil Aleksandrovich Granin. This outstanding person of Russian culture and a public man made a significant contribution to the development of literature and society. Influenced by the ideas of D.A. Granin, many readers have defined their future path in life, becoming engineers and scientists. In the work, numerous archival documents were introduced for the first time in scientific circulation. Their content reveals important facts about the biography of the writer, which have been unknown before. In the article, the authors make a number of significant clarifications that make it possible to correct biographical inaccuracies made by the authors in previous publications.