The book is devoted to the study of the processes of formation and development in the XIX-XX centuries of the Azerbaijani nation, the largest in the South Caucasus. The ancestors of modern Azerbaijanis, who created an ancient and original culture, have sown the eastern part of the South Caucasus from time immemorial. Based on this, a brief historical excursion is also presented to the attention of readers, which traces the main stages of the formation of the Azerbaijani ethnic group. But the main goal of the study is still to comprehend and highlight the cardinal socio-economic and cultural changes at the turn of the 19th - 20th centuries, which led to the formation of the Azerbaijani nation.