In October 2020, an 18th-century manuscript containing hand-coloured drawings and featuring a long title in Russian: Abbreviated Description of the Lena River together with a General Map and Drawings of All Curiosities and Attributes along Its Banks underwent the digitizing process as part of the Jagiellonian Library digitizing ‘Patrimonium’ Project. The work seeming from the writing legacy of Ż. Pauli (1814-1895) was authored by the Russian clerk, Anton Ivanonovich Losev (1765?-1829). Losev was well known in Siberia, and particularly Irkutsk as a land surveyor, geographer, cartographer, historian, and tourism lover. However, in the remaining territory of Russia and Poland, his person and his works are practically unknown. The unique manuscript discovered at the Jagiellonian Library is the topic of this paper. Additionally, it contains the translation of the genuine text into English, which is published here for the first time.