This book offers a wide variety of handicraft works using old cardboard boxes, which makes it easy to start and have fun. While there were a couple of new inspirations for projects my son and I immediately decided to copy, there also was a large number of things we already built in the past, like the knight's helmet or the shield, which are not really original ideas. Also, the builder and fireman pages didn't interest my son at all, he lost interest in those themes years ago, and IMHO they would appeal mostly to younger children.
I liked that every project was suitable for boys, so we didn't have to skip any 'pink pages'. While girls might find the projects equally cool, I guess the book's main audience will be boys, however it is not advertised as such (maybe the examples on the cover image give a hint).
If you never did much handicraft work before, this book may be a good introduction because it provides easy-to-make instructions and you can start immediately because you don't have to buy any fancy stuff to get started. Also, I think that a lot of projects in this book will be of more interest to younger children, though they may still need a little help from a adult.
I guess that maybe one quarter of the book is stuff we decided we want to build, half of the projects we already did in the past and one quarter just didn't meet our interest.
(Thanks to Netgalley, the author, and the publisher for a copy of the book, all opinions are my own)