Ruby on Rails, often just called Rails, is an open-source web application framework written in Ruby that follows the Model-View-Controller (MVC) architectural pattern. Coursera's Ruby on Rails catalogue teaches you how to develop web applications using this powerful framework. You'll learn the principles of the MVC architecture, understand how to use Rails' database abstraction layer, and get to grips with creating, reading, updating, and deleting data in a database using Rails' Active Record. You'll also learn how to use the Rails router to define your application's routing. By the end of your study, you'll have the skills to create robust, scalable web applications using Ruby on Rails, setting you apart in the world of web development.