The Spirit of the Laws

The Spirit of the Laws is a treatise on political theory first published anonymously by Charles de Secondat, Baron de Montesquieu in 1748 with the help of Claudine Guérin de Tencin. Originally published anonymously partly because Montesquieu's works were subject to censorship, its influence outside of France was aided by its rapid translation into other languages.
Montesquieu spent around twenty one years researching and writing De l'esprit des lois (The Spirit of the Laws), covering many things like the law, social life, and the study of anthropology and providing more than 3,000 commendations. In this political treatise Montesquieu pleaded in favor of a constitutional system of government and the separation of powers, the ending of slavery, the preservation of civil liberties and the law, and the idea that political institutions ought to reflect the social and geographical aspects of each community.