ReactJS is an open-source JavaScript library that brings the power of reactive programming to web applications and sites. It aims to address the challenges encountered in developing single-page applications, and is intended to help developers build large, easily scalable and changing web apps. Starting with a project on Open Library API, you will be introduced to React and JSX before moving on to learning about the life cycle of a React component. In the second project, building a multi-step wizard form, you will learn about composite dynamic components and perform DOM actions. You will also learn about building a fast search engine by exploring server-side rendering in the third project on a search engine application. Next, you will build a simple frontpage for an e-commerce app in the fourth project by using data models and React add-ons. In the final project you will develop a complete social media tracker by using the flux way of defining React apps and know about the best practices and use cases with the help of ES6 and redux. By the end of this book, you will not only have a good understanding of ReactJS but will also have built your very own responsive frontend applications from scratch.