The book "Civil War 1918-1921 - a lesson for the 21st century" is a unique journey into the past of the Ukrainian State, when the fires of war and revolution ignited on the land of our Motherland. The author investigates the events of those years, revealing the causes of the conflict, the color of the campaigns of the armed forces, the strategic and tactical moves of the commanders. In particular, the book describes in detail the battles, political ideas, and ambitions of the leaders of the parties that fought on the territory of Ukraine. The importance of the events of that time for the formation of Ukrainian national identity and statehood is emphasized. Readers will have the opportunity to see what important lessons can be learned from past events for building the future in the 21st century. The book "Civil War 1918-1921 - a lesson for the 21st century" will be a useful source for everyone who is interested in the history of Ukraine and the development of universal values of peace and mutual understanding.