This brochure is devoted to the characterization of the oldest embassy book of Crimean affairs, stored in the Main Archive of the Ministry of Foreign Affairs in Moscow. This book is a complete chronicle of the embassy relations of Ivan III Vasilyevich with his ally - the Crimean king Mengli-Girey. It also includes cases on relations with Turkish Kafa and Tsargrad, Kazan, Moldova, Ugria, the Polish-Lithuanian state, since the affairs of these lands were in contact with each other for the Moscow state and Crimea. The book contains a lot of data on the inner life of the Moscow state and the Crimean horde, as well as the entire Tatar-Turkish Muslim world. The presentation of the book is clear and slender, the language is exemplary in purity and correctness. It "is a masterful work of its kind by the order of the embassy clerks of Grand Duke Ivan III; under their pen, the political thought of Ivan the Great received a skillful expression, and all embassy affairs - a clear, distinct presentation."