His specialty is microeconomics, finance, macroeconomics, and money and banking.
Klein's research concerns the establishment and enforcement of human and property rights in the Age of Fighting Sail (1450-1850). As Europe expanded onto the world stage and trade became global, the protection of trade became a crucial aspect to personal and government growth. Klein's work uses the tools of economics to explain and predict the activities of this period.
In addition Klein is the Director of the Institute for the Indies.