This chapter surveys experimental research on public goods, focusing on the fundamental question of whether people are selfish or cooperative in contributing to public good production. The author describes a simple public goods experiment and provides methodological and theoretical background. Early experiments by Bohm, Dawes et al., Marwell et al., and Isaac et al. are reviewed, highlighting their procedures, results, and comments. The chapter then explores factors that improve cooperation, including thresholds, experience, repetition, and communication. It discusses the challenges of controlling variables in public goods experiments and the sensitivity of outcomes. The author emphasizes the importance of understanding behavior in public goods environments for policy design and institutional choices. The chapter concludes with a discussion of the range of public goods environments and the need for more systematic research to advance the field.This chapter surveys experimental research on public goods, focusing on the fundamental question of whether people are selfish or cooperative in contributing to public good production. The author describes a simple public goods experiment and provides methodological and theoretical background. Early experiments by Bohm, Dawes et al., Marwell et al., and Isaac et al. are reviewed, highlighting their procedures, results, and comments. The chapter then explores factors that improve cooperation, including thresholds, experience, repetition, and communication. It discusses the challenges of controlling variables in public goods experiments and the sensitivity of outcomes. The author emphasizes the importance of understanding behavior in public goods environments for policy design and institutional choices. The chapter concludes with a discussion of the range of public goods environments and the need for more systematic research to advance the field.