The Go `context` package manages request-scoped values, cancellation signals, and deadlines across goroutines and API boundaries. Key functions: - **Cancellation**: Propagate cancellation via `WithCancel()`, `WithTimeout()`, or `WithDeadline()`. - **Values**: Pass request-scoped data safely with `WithValue()`. - **Best Practices**: Pass contexts explicitly (first function parameter), avoid structs in values, and check `ctx.Done()` in loops/long-running tasks to prevent leaks. Used in HTTP servers, databases, and distributed systems for graceful termination and timeouts. (30 words)