More like Sir Barely-Appearing-In-This-Book.
There's no realistic usage of mathematics in this. There's no engineering or practical application of anything. It feels like the author had an ending in mind, maybe just the title of the book, and wanted to write something based on Euler characteristics, so she had to make some kind of weird, contrived situation for them to derive Euler characteristics on their own. Everything they do is just super lucky. I don't know who's going to enjoy this book. People who are really gung-ho about math, I guess.