Chaos engineering builds resilient systems by deliberately introducing controlled failures. This proactive approach helps identify vulnerabilities before they cause real outages. It is particularly crucial for complex, distributed cloud-based systems where traditional testing is insufficient. Cloud resiliency features alone do not guarantee application fault tolerance. Chaos engineering transforms worst-case "what if" scenarios into prepared responses, fostering calm confidence in teams. The methodology, pioneered by Netflix and Google, involves defining a system's normal state and then running experiments to observe its reaction to disruptions. Key principles include hypothesizing steady states, replicating real-world conditions, running experiments in production, automating tests, and carefully managing the blast radius. Practices involve defining steady states, formulating hypotheses, using controlled environments, injecting failures, and automating execution to derive actionable insights. Experiments consist of planned procedures with actions, probes, and rollbacks to test the system's response. Tools like Chaos Toolkit and Google Cloud-specific recipes can help teams get started with implementing chaos engineering.