Adam Smith was the author of "The Wealth of Nations," published in 1776. This influential work is often considered the foundation of modern economics. In it, Smith explores the nature of wealth, the role of free markets, and the importance of competition and self-interest in promoting economic growth. He introduced key concepts such as the "invisible hand," which describes how individual self-interest can lead to beneficial social outcomes. Smith's ideas challenged mercantilism and advocated for a system of economic liberalism, laying the groundwork for classical economics. His insights into division of labor, productivity, and trade continue to resonate within economic theory today.