The article deals with one of the outstanding personalities of the Kazakh people, Khan of the Junior Zhuz Abulkhayir and his epistolary heritage. Many scientific works have been devoted to the personality of Abulkhayir Khan, and scholars-researchers evaluate his policy in different ways, especially the issue of joining the Junior Zhuz to Russia. In Soviet times, based on the subjective views of the Orenburg governor I.I. Neplyuev formed a one-sided idea about the personality of Abulkhayir. The famous scientist I.V. Yerofeyeva did a great job in changing the prevailing one-sided view of the personality of the khan. Irina Viktorovna offered a reasoned interpretation of the motives for the rapprochement of the Khan of the Junior Zhuz Abulkhayir with the Russian Empire.  Also, the letters of Abulkhayir Khan included in the collection “Epistolary heritage of the Kazakh ruling elite of 1675-1821” released by the scientist in 2014 are a valuable source for researchers on the new history of Kazakhstan. Based on the epistolary heritage of Abulkhayir Khan, the author reveals his personality and cites interesting historical facts. The article also discusses new scientific publications regarding the policy and activities of the Khan of the Junior Zhuz.