Short answers, pulled from the story.
Liberalism is a political and moral philosophy based on the rights of the individual, liberty, consent of the governed, political equality, the right to private property, and equality before the law. It generally supports liberal democracy, market economies, individual rights, secularism, the rule of law, and freedoms of speech, press, assembly, and religion. It is frequently cited as the dominant ideology of modern history.
The English philosopher John Locke is often credited with founding liberalism as a distinct tradition and is generally regarded as the father of modern liberalism. In his Two Treatises of 1690 he argued that each man has a natural right to life, liberty, and property, and that governments must not violate these rights. He also concluded that the people have a right to overthrow a tyrant.
Classical liberalism advocates free-market and laissez-faire economics, civil liberties under the rule of law, limited government, and individual autonomy. Social liberalism, which emerged in Britain around 1900, endorses a regulated market economy and the expansion of civil and political rights, holding that individual liberty requires favourable social and economic conditions secured by an interventionist state. Since the 1930s the bare word liberalism in the United States usually means social liberalism.
Liberalism became a distinct movement in the Age of Enlightenment, gaining popularity among Western philosophers and economists. Its first major political signs appeared at the time of the English Civil War, and the Glorious Revolution of 1688 enshrined parliamentary sovereignty and the right of revolution in Britain. The first use of the word liberalism in English appeared in 1815.
Leaders in the British Glorious Revolution of 1688, the American Revolution of 1776, and the French Revolution of 1789 used liberal philosophy to justify the armed overthrow of royal sovereignty. In France the abolition of feudalism on the night of the 4th of August 1789 and the Declaration of the Rights of Man and of the Citizen marked the triumph of liberalism, the latter itself based on the U.S. Declaration of Independence of 1776.
John Maynard Keynes, who lived from 1883 to 1946, gave the definitive liberal response to the Great Depression. In The Means to Prosperity in 1933 he recommended counter-cyclical public spending, and in The General Theory of Employment, Interest and Money in 1936 he justified interventionist government policy to stimulate demand during high unemployment. He introduced the concept of price stickiness to explain stable unemployment equilibria.