The Amazon Builders' Library article "Instrumenting distributed systems for operational visibility" by David Yanacek explores the importance of instrumentation in understanding how a system works, particularly in distributed systems. The article highlights that traditional logging tools such as cat, grep, sed, and awk are not sufficient for serverless applications, instead emphasizing the need for specialized tools to create a real map of interacting resources. Instrumentation frees developers from manually logging every statement, automatically recording important data points to debug crashes or improve performance. The article also discusses the role of trace IDs, logs, alarms, and thresholds in instrumentation, as well as best practices such as trimming large requests, protecting sensitive data, and pruning unnecessary log statements.