Backbone is a JavaScript MVC framework that helps address problems with coding style differences, spaghetti code, and lack of classes in web applications. It advocates an MVC approach with separate models, views, and controllers. Models store and sync data, views handle the UI display and user interaction, and controllers manage the flow between models and views. Backbone promotes clean, reusable code by binding events to models so views automatically update when data changes. It also uses Underscore templates to generate HTML from data.