This is a children’s book about Eratosthenes, the librarian and mathematician who forst thought out a way for measuring the circumference of the planet. The book has an intro that basically states that the author made up the parts of Eratosthenes' early childhood since no records survive of how he really lived. Drawing on historical account of the time, they paint a picture of their estimation of what a smart Greek child must have been like, and extrapolate from there. The book was well-illustrated and clearly explained the procedures that Eratosthenes went through