Eratosthenes and the Measurement of the Earth's Circumference (c.230 BC) is an innovative and thought-provoking examination of one of the pivotal moments in the history of science. This text analyses a debate that has been going on for more than 2,300 years over the accuracy of Eratosthenes' experiment and calculations and puts to rest all prior theories that have come before. This work engages with this long running debate by applying innovative and multi-disciplinary methods such as linguistic analysis, mathematical modelling, satellite mapping, archaeological investigation and historical examination that creates the first ever combined exploration of this important event in the history of astronomy.