Thucydides' Histories is a seminal work of historiography that recounts the first 20 years of the Peloponnesian War between Athens and Sparta. Written by the Athenian historian Thucydides, it is considered one of the earliest scientific and objective accounts of a historical event and has had a profound influence on Western historiography. The work is divided into eight books, with the seventh book covering the events of 424-421 BC, including the Sicilian Expedition and the Peace of Nicias. Thucydides' Histories is renowned for its detailed and analytical approach, providing insights into the political, military, and social dynamics of the Peloponnesian War. It remains an essential text for understanding ancient Greek history and the nature of warfare and conflict.