The book is dedicated to the least studied period of the life of the great Russian poet - the events of 1841 and the last days of the life of Mikhail Yuryevich Lermontov. The author, based on documentary data, testimony from contemporaries, and new archival materials, convincingly proves that there was no conspiracy to kill the poet. The book traces with chronological accuracy day by day Lermontov's life in the Caucasian Mineralnye Vody in the summer of 1841, all the events and circumstances that preceded the duel. The author introduces unpublished or forgotten documents into scientific circulation. Based on documentary evidence, new characteristics of the people surrounding the poet in those fateful days are given. The Caucasian notes of the Decembrist V.S. are published in the Appendices. Tolstoy and the unknown article by V.A. Manuylov about the mystery of the origin of Yu.M. Lermontov.