This document discusses the labor market and unemployment. It begins by outlining different types of unemployment like frictional, structural, and cyclical unemployment. It then discusses the classical view that the labor market always clears through adjustments in wages. Several theories for why unemployment exists are presented, including sticky wages, efficiency wage theory, and imperfect information. The relationship between unemployment and inflation is explored through the Phillips Curve, though it is noted this relationship is more complex than originally thought. In the long-run, the natural rate of unemployment and NAIRU are introduced.