Keynes's definition of involuntary unemployment in Chapter 2 of the General theory is examined using supply and demand diagrams. Critics argue that the definition is overly complex, with two versions identified as Mark I and Mark II. Both classical and Keynesian theories see an excess supply of labor as a cause of unemployment, making it hard to distinguish between voluntary and involuntary unemployment. While the concept of involuntary unemployment is not as prominent today, debates on self-adjusting economies and COVID's impact on unemployment bring related issues to light.