Henry George was an American writer, politician and political economist, who was the most influential proponent of the land value tax, also known as the "single tax" on land. He inspired the economic philosophy known as Georgism, whose main tenet is that people should own what they create, but that everything found in nature, most importantly the value of land, belongs equally to all humanity. His most famous work, Progress and Poverty (1879), is a treatise on inequality, the cyclic nature of industrialized economies, and the use of the land value tax as a remedy.