async_hooks is a Node.js core module that provides an API for tracking the lifecycle of asynchronous resources in a Node.js application. It enables developers to monitor, debug, and profile asynchronous operations, such as callbacks, promises, and timers. By using async_hooks, developers can gain deeper insights into the execution flow of asynchronous code, which is especially useful for diagnosing issues like memory leaks or context loss. The module allows the registration of hooks that are triggered at different stages of an asynchronous resource's lifecycle, such as initialization, before and after execution, and destruction. This makes it a powerful tool for building advanced debugging and monitoring solutions in Node.js environments.