Karl Polanyi was a Hungarian economist and social theorist, best known for his book, "The Great Transformation," published in 1944. He argued that the rise of the market economy in the 19th century disrupted social relations and led to significant social and economic upheaval. Polanyi emphasized the importance of social and cultural factors in economic systems, challenging the idea that markets operate independently of society. Polanyi introduced the concept of the "double movement," which describes the push and pull between market forces and social protections. He believed that while markets can drive economic growth, they also create inequalities that society must address through regulations and social policies. His work has influenced various fields, including sociology, political science, and economic history.