Short answers, pulled from the story.
Liberty is the state of being free within society from restrictions imposed by authority on one's way of life, behavior, or political views. The concept varies by perspective and context, and is sometimes distinguished from freedom by meaning the absence of arbitrary restraints that takes into account the rights of all involved.
In his 1958 lecture "Two Concepts of Liberty", Isaiah Berlin framed negative liberty as a condition in which an individual is protected from tyranny and the arbitrary exercise of authority. Positive liberty refers to the liberty that comes from self-mastery, the freedom from inner compulsions such as weakness and fear.
Thomas Hobbes, who lived from 1588 to 1679, defined a free man as one not hindered from doing what he wills among the things he is able to do by his strength and wit. John Locke rejected that view, arguing that freedom is constrained by laws in both the state of nature and political society, and attacked Sir Robert Filmer, who held the same definition as Hobbes.
The modern concept of political liberty has its origins in the Greek concepts of freedom and slavery, where to be free was to have no master and to live as one likes. Aristotle linked this directly to democracy, though in Athens it applied only to free men, and women could not vote or hold office.
Liberty developed through a series of charters and statutes, including the London Charter of Liberties in 1066, the Charter of Liberties in 1100, and the Assize of Clarendon in 1166. Magna Carta, enacted in 1215, became the cornerstone of liberty in England, followed by the Petition of Right in 1628, the Habeas Corpus Act in 1679, and the Bill of Rights in 1689.
Liberalism, per the Concise Oxford Dictionary of Politics, aims to preserve individual rights and maximize freedom of choice, with toleration at its core. Libertarianism holds liberty as its primary value and follows the Non-Aggression Principle, opposing governmental coercion. Socialists view freedom as a concrete situation requiring material economic conditions, and for Karl Marx it is only fully attainable in a communist society of superabundance.
The 1776 United States Declaration of Independence named "Life, Liberty and the pursuit of Happiness" as a natural right. That declaration was troubled for 90 years by legalized Black slavery, upheld in the 1857 Dred Scott decision, before the Constitution was amended in 1866 and voting rights were extended to women in 1920.