This chapter considers how people use knowledge to make informed decisions for themselves and their households, and the relationship between codified and tacit knowledge as found in experience and learning by doing. Tests of financial literacy presuppose that financial decision-making involves the application of well-defined rules to the world at large. The financial literacy programme is also a recipe for public policy in that, if individuals’ knowledge can be deepened in relation to a broad class of financial issues, then social welfare will (presumably) be advanced. Individual decision-making in the context of financial risk and uncertainty has implications for how behaviour is conceptualized and modelled in economics and in economic geography. The chapter discusses the principles of financial literacy, which were used to represent axioms or statements about how financial markets work and the appropriate behavioural responses. One implication is that German households have not had to acquire the same level of financial literacy as Anglo-American households.