Measuring space is crucial to our process of knowledge. Archimedes is a pioneer of geometry, in its most literal sense as the "measurement of the earth." He was the first to measure curved bodies in space and to calculate the surface area and the volume of the sphere. His method was brilliant, and it influenced all the great protagonists of modern science. From Galileo, who would revisit his proofs with a new sensitivity; to Gauss, who extended his calculations with astonishing consequences; to Einstein, who discovered one of the most famous equations in the history of Science, the Field Equation. An expression that can be thought of as the contemporary version of Archimedes' formula. The book is addressed to anyone interested in exploring reality with the help of a measure.