Field experiments embed data collection within natural social environments, offering a powerful tool allowing researchers to study real-world behaviors and identify causal effects. They are particularly valuable for advancing theory, testing causal claims, and informing policy, especially in research areas such as discrimination, prejudice, and prosocial behavior. This chapter focuses on field experiments that employ concealed observation, allowing researchers to minimize biases related to participant awareness, such as social desirability. We also highlight recent developments in field experimental methods, including digital field experiments that leverage online platforms and tools. The chapter addresses both the strengths - such as increased external validity - and limitations, including ethical concerns and challenges in maintaining control over experimental conditions. Finally, using an empirical example from a study on everyday discrimination in public transit, we provide a hands-on example demonstrating how to analyze field experimental data.