Node.js is built on the principle of event-driven programming, a model that allows you to build highly scalable and efficient applications. In traditional synchronous programming, operations are executed one after another, and each task must finish before the next begins. This can lead to inefficiencies, especially when dealing with tasks that take time, such as reading files or making network requests. In contrast, event-driven programming enables your application to respond to events as they happen, without waiting for each task to complete before moving on.

In an event-driven model, your code listens for specific events and reacts to them when they occur. This allows Node.js to handle many connections or operations at once, making it particularly suited for I/O-heavy applications like web servers. The main advantages of this approach include improved scalability, efficient resource usage, and the ability to write non-blocking code that remains responsive even under heavy load.

Node.js implements this model using event emitters and listeners. When an event occurs, an emitter notifies all listeners registered for that event, triggering the appropriate response. This separation of concerns leads to cleaner, more modular code and allows you to handle asynchronous operations in a natural way.