Occasionally I use Drupal in combination with front-end frameworks, and this book offers a complete and nice overview to catch up with the current state of decoupled Drupal architectures. The examples for React use classes instead of hooks, but it's understandable since the book has been completed in 2018. However, it's not clear why the author uses the now deprecated componentWillMount() for fetching data, instead of the recommended componentDidMount(). Overall, a nice book.