This book is for developers who have heard about web components, but don't really know where to start. This book is also for intermediate and advanced developers who know what web components are, but are still afraid to use them in production. This book is also for frontend engineers who are simply looking into web components in order to increase their knowledge and skills.
You can also use this book to learn about and get into component-driven methodologies. If you are coming from a React/Angular/Polymer background, this book will give you an insight into how most things can be achieved using vanilla JavaScript without any libraries.