This book is ideal for readers who want to start creating internet-connected projects themselves, but only have a little bit of experience of programming and using the Arduino IDE. You do not need to have a computer science background to follow along. Simply curiosity and a basic understanding of programming in Arduino will be enough. If you understand basic programming concepts such as variables, loops, conditions, and functions, then you will have no problem following along.
Some of the chapters touch on a lot of different topics. I do not expect you to understand every single bit in detail. The goal here is to give you a general overview of related technologies and techniques, so you can dive into any of the topics after finishing the book. You can look at it as a starting point for IoT prototyping.
For an intermediate or professional programmer, the pace of the hands-on projects in this book might feel a bit slow, but there is plenty of relevant information for you in the theoretical chapters as well, including how to use MQTT.