A very short book about Docker. Similar to reading random blog posts on the Internet. If you don't know Docker already (at least to have some idea about it), you might finish the book and observe that there are no differences in your knowledge.
The structure is a bit weird. Maybe it is a cultural thing, or it is expecting the reader to know more than what I would call a beginner. The composition is strange too. Sometimes I thought it was done by someone cutting and pasting articles from the Internet, without really knowing the subject retrieved. Other times it looks like some of the applications that summarize content.
The positive is that it is very short, you can finish it in an hour, including trying a couple of things in your computer. The negative is that you will probably feel that there were better ways to spend an hour.