It is obvious that the first place you need to visit, when you want to learn React is its official page – facebook.github.io – there you can find all the documentation you need and even some tutorials.
If you want to learn React online, you absolutely should see – Egghead.io – they currently have 139 lessons divided into: React fundamentals, React Native Fundamentals, React Flux Architecture with ES5 and ES6, Getting Started with Redux, Building Your First App, and React Testing Cookbook. Here you can also find lessons made by such professionals as: Tyler McGinnis, Joe Maddalone, Trevor D. Miller, Dan Abramov. Most of the lessons are paid, but there are some free to watch. You get the option to rate it on your own.
Structor – a user interface builder for React made by Aleksander Pustovalov and his team. Previously known as React UI Builder. Citing Structor’s makers – this is “Swiss Army knife in UI development.” Personally, I think it is a very nice tool, which can save you a lot of time. More information can be found here at http://www.npmjs.com/package/structor.
Finally, let’s have a look at some books – there is an interesting position written by Juho Vepsailainen, “SurviveJs – Webpack and React. From apprentice to master.” With this book priced at $19.99, you can learn how to build a simple application with Webpack based development and production environment. Among other things, you can also learn basics of Alt, an implementation of Flux application architecture.
Second worth to mention position is – “React.js Essentials. A fast-paced guide to designing and building scalable and maintainable web apps with React.js.” You will be taken on a fast-paced journey through building your own ReactJS application. Book adopts a step-by-step approach with some samples of code.