Widely considered to be the best history books ever written.
Had a huge influence on very many important Western politicians and historians of the past two centuries.
About the book (from wikipedia):
The History of the Decline and Fall of the Roman Empire was written by English historian Edward Gibbon and published in six volumes between 1776 and 1789. It is an exceptionally well written book on history.
The work covers the history of the Roman Empire, Europe, the Catholic Church, the Byzantine Empire, the rise of Islam, the Crusades, etc etc from 98 to 1590 and discusses the decline of the Roman Empire in the East and West. Because of its relative objectivity and heavy use of primary sources, at the time, its methodology became a model for later historians. This led to Gibbon being called the first “modern historian of ancient Rome.”
Edward Gibbon (27 April 1737 – 16 January 1794) was an English historian and Member of Parliament.