The book provides good, simple explanations of geometric truths that lay at the root of how early artisans used geometry and proportion to build and create, instead of direct measurements and arithmetic. Many of the tools that were created from these geometric truths would still be useful today. This book seems to be written for younger readers, although the explanations require some thought. A basic understanding of geometry helps. Two other books by these authors provide more details on the concepts of artisan geometry, and the tools used: "By Hand and Eye" and "Euclid's Door." All the books are published by Lost Art Press. The books are also available at the author's website: https://www.byhandandeye.com/product/..., which also contains a lot of additional educational materials on the use and construction of the tools mentioned in this book.
A fun, illustrated book about historical measuring tools of the ancients and how to use them. While not of direct use for the most part, the geometric constructions are fun to look at as as the practical examples. Not much verbiage, you can finish it in one sitting. Might make a good present to young engineering nerds in training.