Professor Emeritus of the University of Athens, Maro Papathanasiou, forewords.

This volume includes books e', f', g', h' and i' of the "Elements". Book E contains Eudoxus ' theory of proportions and Book V contains the applications of proportions in Plane Geometry. Books g', h', i' are the Numerical books of the "Elements" and deal with the nature and properties of natural numbers, which are represented by straight lines.