Middleware in Django is a framework that allows you to process requests globally before they reach the view. It’s crucial for tasks like authentication, session management, and modifying request/response objects.

Middleware is a fundamental aspect of Django that acts as a hook into Django’s request/response processing. It's a layer that sits between the request and response cycles, allowing developers to process requests globally before they reach the view and to modify responses before they are sent to the client. Middleware can be used for various purposes, including session management, authentication, logging, and handling cross-site request forgery (CSRF) protection. By defining middleware, developers can encapsulate functionality in a reusable manner, enhancing code organization and promoting separation of concerns. For instance, you can create custom middleware to log user activity or to ensure that users are authenticated before accessing certain views. Django comes with several built-in middleware classes that handle common tasks, and you can easily add your own. Properly utilizing middleware can significantly streamline application behavior and enhance security, making it an essential consideration in Django full stack development.