In the Handbook of Public Economics, vol. 5, top scholars provide context and order to new research about mechanisms that underlie both public finance theories and applications. These fundamental subjects follow the recent, steady movement away from rational decision-making and toward more personalized approaches to tax generation and expenditure, especially in terms of the use of psychological methods and financial incentives. Closely scrutinized subjects include new research in empirical (instead of theoretical) public finance, the methods for measuring taxes (both in revenue generation and expenditure), and the roles that taxes play in specific settings, such as emerging economies, urban settings, charitable giving, and among political entities (cities, counties, states, countries). Contributors look at both the "tax" and "expenditure" sides of public finance, emphasizing recent influences that psychology and philosophy have exerted in economics with articles on behavioral finance, charitable giving, and dynamic taxation. To a field enjoying rapid growth, their articles bring context and order, illuminating the mechanisms that underlie both public finance theories and applications.