Librarian Who Measured the Earth — Kathryn Lasky

This colorfully illustrated biography of the Greek philosopher and scientist Eratosthenes, who compiled the first geography book and accurately measured the globe's circumference, is just right for budding mathematicians, scientists, historians, and librarians! Filled with fascinating details about Eratosthenes's world (and in print since 1994), kids are sure to flip through the pages time and again.