Node.js is a powerful open-source environment that allows for the execution of JavaScript code on the server-side, offering a platform to build fast and scalable network applications. Coursera's Node.js catalogue teaches you about the foundational concepts and practical applications of Node.js. You'll be immersed in understanding the asynchronous, non-blocking nature of Node.js, its event-driven architecture, and its usability in creating web servers, REST APIs and real-time applications. Additionally, you'll gain knowledge about Express.js for web application development, and managing data with MongoDB and Mongoose. This skill is invaluable for full-stack developers aiming to enhance their backend development capabilities.