"Wage Labour and Capital", or "Capital and Labour", is a text by Karl Marx in which he describes labor relations within capitalist society.

One key aspect emphasized in Marxist discussion on labor and wages involves the concept of surplus value, which subjugates individuals to selling their labor power, creating an excess return from production—typically in financial value—for the owner of the means of production.

Marx illustrates surplus value through the example of an eight-hour workday: in this framework, the first four hours generate the productivity needed to cover production costs, while the remaining four hours create surplus value. This surplus is the basis for accumulation in the finances of the owner, whether an industrialist, a merchant, or anyone who employs labor as a productive force.

For Marx, this surplus is not only a value that exceeds production costs but also a potential source for building new capital. It can be reinvested in different areas or used to expand production, highlighting how surplus value fuels the continuous cycle of capitalist accumulation.