This section defines wages as the monetary form of the price of labour-power and identifies three conditions of the modern wage system: legally free labourers who can sell labour-power, the separation of workers from the means of production, and the development of commodity–money relations. It then contrasts wage labour with earlier labour forms—slave labour and corvée labour—showing how “payment” and surplus extraction take different forms under different social relations. Finally, it emphasizes that the transition to wage labour is historically uneven and often produces hybrid arrangements in which labour appears as a commodity while retaining tributary features, a dynamic that helps illuminate wage forms in China.