Developed by Facebook engineers, React is a JavaScript library that has revolutionized how developers design and think about views in web applications. It introduced a way for developers to declaratively describe user interfaces, and to model the state of these interfaces instead of the transactions on them. In React.js Succinctly, author Samer Buna introduces the novel approach to building user interfaces that React provides, and walks readers through the basics of declarative user interfaces, React components, working with user input, and more.
I'm personally a fan of this Succinctly series from Syncfusion. Small books and right to the point, with enough information to get you started with the technology in hand and an overview of the problem it tries to solve.
But what sets "React.js Succinctly" apart from the other books of the series I've read so far is the challenge posed by the author in the last chapter. Samer Buna gives you the opportunity to solve a really nice game, fun to develop, with some bugs intentionally included and a detailed description of the strategy taken by him to solve it piece by piece.
I would recommend the book for someone that have a fair knowledge of javascript but knows little to nothing about React.