Who was the theory of surplus value?

The theory of surplus value was developed by Karl Marx, a 19th-century philosopher and economist. It posits that the value produced by labor exceeds the wages paid to workers, creating surplus value that capitalists appropriate as profit. This concept is central to Marx's critique of capitalism, highlighting the exploitation of labor and the inherent inequalities within capitalist systems. Marx argued that this surplus is the source of capital accumulation and class struggle.