This essay surveys both the traditional findings and new debates that have used the Spanish imperial royal financial accounts to analyze the colonial economy and government. The crisis of the seventeenth century, the relations between colonial elites and royal government, the impact of income transfers among treasury offices, the sale of offices, the system of voluntary loans, the eighteenth-century reforms, and the influence of the tax system on the evolution of the colonial economy and society have all created a new set of questions and debates that historians, economists, and political scientists have engaged in. There is both consensus and disagreement on what these numbers mean for various groups in the society as well as long-term institutional developments. Just as new approaches have opened up new area for research, there is also a great deal of unexplored topics that can be developed using the unpublished primary accounts.