The book "History of the Peloponnesian War" written by the influential Athenian strategist Thucydides is one of the most significant works of ancient Greek historiography. In his work, Thucydides tells about the war between the Athenian and Peloponnesian leagues in the 5th century BC, which lasted more than twenty years. The author carefully describes the causes of the conflict, the course of the war, and the political and military strategies of both sides. He examines the reasons for the defeat of Athens and expresses his own thoughts about the suffering caused. "The History of the Peloponnesian War" is considered a classic example of an objective historical scientific work that reflected an important stage in the history of Greece.