I agree it is. But just I took a quick look at the book, while I understand the book is not done yet, looking at the table of contents, I doubt this would help. Like, do you have to cover kerberos, IP Subnetting, OSI IP model, Agile, git, REST API, docker, and many more in a single book about "data engineering"? If anything, it would confuse beginners even more. Its like the author tried to cram as many buzzwords as possible into a single book.
However, I don't think the purpose of this book is to cover these subjects in their entirety. Most of the time, with books like these, I would just like to see definitions, use cases, why it's used, maybe even what it replaced in the space it exists in. Materials like this aren't meant to make you an expert, they are just meant to show you what's out there, why it's out there, and (maybe) what was out there before. They give you context with which to google things.
Either way, everyone expects something different from educational materials. I personally would not use this book, but I get the idea he was going for.