Classical liberalism espouses limited government and freedom for citizens when it comes to expression and lifestyle choices, including the freedom to worship as one wants, to make a living as one chooses and to raise one's family without government interference.
Classical liberalism is not so much a political philosophy as a synthesis of ideas that have developed over the past several thousand years and then more explicitly in Western Europe, especially within Anglo-American culture in the 19th and 20th centuries.
Classical liberalism espouses the workings of Adam Smith's Invisible Hand of the market to create a better life for all through the magic of natural marketplace competition. Emphasizing the free market rather than state authority, classical liberalism is naturally anti-authoritarian and stresses the primacy of the individual and the family unit (rather than state control).
In the United States, the term "liberal" – which means "classical liberal" in Europe – was perverted in the 20th century and came to mean something approaching "socialist," defining "liberals" as people who believe in the efficacy of government action to influence society and generate prosperity. Thus in the US a new term has sprung up – libertarianism – which promotes much the same market-driven agenda as 18th century classical liberals so as to not be conflated with the modern definition of liberalism. However, US-style libertarianism tends to be more radical in some of its incarnations than 18th century Anglo-dominated classical liberalism.
Many English and Scottish philosophers contributed to the rise of classical liberalism as an economic and political philosophy in the 18th century when it had its heyday as a political movement. In the 21st century, classical liberalism has re-emerged in the United States as a driving political force, and many of its concepts are now espoused by the original messages of America's growing Tea Party movement.
Rather than being a spent force, classical liberalism and its more radical cousin, libertarian anarchism (absence of the state in favor of market discipline), are becoming two of several dominant sociopolitical belief structures of the 21st century, as is another competing ideology known as "Conservatism."