Short answers, pulled from the story.
Montesquieu is best known as the principal source of the theory of separation of powers, which divides government into legislative, executive, and judicial branches. He outlined this theory in The Spirit of Law (De l'esprit des lois), published in 1748. He also did more than any other author to establish the word despotism in the political lexicon.
According to a survey by political scientist Donald Lutz, Montesquieu was the most frequently quoted authority on government and politics in colonial pre-revolutionary British America, cited more than any source except the Bible. James Madison of Virginia, known as the Father of the Constitution, drew directly on Montesquieu's analysis of separated powers when drafting the U.S. Constitution.
The Spirit of Law was published anonymously in 1748 and translated into English by Thomas Nugent in 1750. It was received enthusiastically in Great Britain and the American colonies, but was denounced by the Sorbonne and placed on the Catholic Church's Index of Prohibited Books in 1751.
Montesquieu argued in The Spirit of Law that climate and geography shape human character and political institutions. Cold climates, he claimed, strengthen the body and produce courage and resilience; hot climates relax the body and foster emotional volatility. He acknowledged that laws and customs could counterbalance these environmental tendencies rather than being absolutely determined by them.
Montesquieu was born on the 18th of January 1689 at the Château de la Brède, 25 kilometres south of Bordeaux in southwest France. He died on the 10th of February 1755 in Paris from a fever and was buried in the Église Saint-Sulpice.
Montesquieu argued in The Spirit of Law that slavery was inherently wrong because all humans are born equal. To illustrate the absurdity of pro-slavery reasoning, he constructed a satirical hypothetical list of arguments in favor of slavery, presenting them without endorsement, including the claim that sugar would become too expensive without enslaved labor.