Jonathan explains seemingly complicated concepts in a simple manner so that everyone can understand. If you are a tester working on web applications and want to gain some technical awareness around programming and automating your tests, this is a great book to start your journey. For example, Jonathan examines how RESTful services work and shows by using examples to explain how to test.
If you are a programmer, this book will help you understand the importance of building testability into your code, and give you some helpful hints on working with tests. You also might find useful other areas that I have seen programmers struggle with such as when to mock or why should you write tests first to help test your assumptions.
I like the way Jonathan uses the automation test pyramid to talk about the layers of testing and tells you climb as necessary starting with unit tests. He emphasizes the importance of testers and programmers collaborating to get the best value of out of automation at all levels.
This book is aimed at beginners, but there are many good tips for everyone working with testing your web-based software.