Welcome to your big-picture guide to the React ecosystem. If you’re new to React and looking to become a professional React developer, this book is for you. This updated sixth edition reflects the current state of React, including coverage of React frameworks and TypeScript. Part 1 introduces you to React. You’ll discover JSX syntax, hooks, functional components, and event handling, learn techniques to fetch data from a server, and tackle the tricky problem of state management. Once you’re comfortable with writing React in JavaScript, you’ll pick up TypeScript development in later chapters. Part 2 transitions you into React Native for mobile development. React Native goes hand-in-hand with React. With your React knowledge in place, you’ll appreciate where and how React Native differs as you write shared components for Android and iOS apps. You’ll learn how to build responsive layouts, use animations, and implement geolocation. Finally, a new chapter shows you how to use AI as a learning partner, covering practical workflows for AI-assisted debugging, evaluating AI-generated code, recognizing common pitfalls in React and React Native output, and writing code deliberately to deepen your understanding. By the end of this book, you’ll have a big-picture view of React and React Native, and be able to build applications with both.