I gave it a five because i really liked the way it was written,he includes the history of the square as Well,and also explains the tables stamped on the square,great drawings and explanations,includes lots of stuff you can do with the square you probably never heard of before,a must have for all who use the square
Lots of math. It seems more for builders and carpenters than woodworkers, but some good info on what all those marks are on a carpenter's square. A short bit on other types of squares, but mostly focused on the one type.