This book is a lightly fictionalized biography of the Greco-African mathematician, Eratosthenes. It tells the story of how he discovered a method to correctly calculate the circumference of the earth nearly two thousand years before Christopher Columbus sailed the ocean blue on much less accurate information. It is also about the importance of asking questions and of looking for answers when there are none. 

Since very little is known about Eratosthenes’s personal life, the book instead uses Eratosthenes as a way to explore topics like ancient Greek education and life in the Greco-Egyptian city of Alexandria. The most interesting part is its description of the Library of Alexandria. Eratosthenes was head librarian there for many years, and the book uses that as an opportunity to explore not only the Library itself, but also ancient books, and the lives of the scholars and teachers living there.  

This book is a great biography, a great introduction to basic geometry, and a great look into an important time in the history of math and science. Kathryn Lasky’s writing style is easy to read, and she provides pronunciation guides for the long Greek names. Kevin Hawkes’ illustrations are soft and dreamy, rather like early impressionist paintings. They are filled with characters of different races and ethnicities, which reflects the real diversity of ancient Alexandria. I would recommend this book for primary school children who are intellectually curious, and for anyone who loves learning. – Krishni Burns