This chapter explains and illustrates why the Australian Constitution is mostly concerned with power, and public power in particular. ‘Public power’ here refers to the powers conferred by the Commonwealth and State Constitutions upon the instruments of government. In this light, the chapter is about how there is a greater focus in the Australian legal system upon power, as opposed to rights. It first describes the nature of the structures established by the Commonwealth and State Constitutions. Then the nature of the limitations of, and interactions between, the powers conferred upon those structures is considered, illustrating the different qualities of legislative, executive, and judicial power and the different relationships between those powers.