A Quick Trip through the Elements

To get an idea of what's in the Elements, here are a few highlights in the order that they appear:

Book I on basic plane geometry

Book II on geometric algebra

Book III on circles and angles

Book IV on constructions of regular polygons

Book V on Eudoxus’ abstract theory of ratio and proportion, abstract algebra

Book VI on similar figures and geometric proportions

Book VII on basic number theory

Book VIII on continued proportions (geometric progressions) in number theory

Book IX on number theory

Book X on classification of irrational magnitudes

Book XI on basic solid geometry

Book XII on measurement of solids

Book XIII on constructing regular polyhedra