Supervisor is a popular Python application that lets you control and monitor process state on UNIX-like systems. We'll talk about Supervisor's history and its most basic usage, including how to start and stop programs using supervisor and its most basic configuration. We'll show its RPC API, which allows you to automate supervisor-related tasks. We'll describe the concept of "event listeners" which are programs that receive messages from supervisor when some state has changed, and which can send email or other types of messages, and start, restart, or stop processes. We'll show how real-world supervisor deployments might go, including how to use the Supervisor installation that's already on your operating system as well as using ``supervisord`` inside a Docker container. Finally, we'll describe what's coming up in Supervisor's future.