# Euclid

**Euclid of Alexandria** - (325 BC - 265 BC).

Greek mathematician, teacher and author of thirteen books on fundamental aspects of geometry and the integers that have come down to us as The Elements.

Euclid's dates are commonly given as above but even this much is not certain about the man who wrote what is possibly the most important and widely read textbook in the world. In the preface to the 2nd edition of the late Sir Thomas Heath's translation he says:

- "So long as mathematics is studied, mathematicians will find it necessary and worth while to come back again and again, for one purpose or another, to the twenty-two-centuries old book which, notwithstanding its imperfections, remains the greatest elementary textbook in mathematics the world is privileged to possess."

What we do know is that despite his fame, Euclid almost certainly did not write the book. What he did was to compile all of the mathematical knowledge available up to that time in a logical and systematic fashion, so that each statement is the logical consequence of all that has gone before. Starting with the definitions of the most basic and fundamental parts of geometry; 1. A point is that which has no part. 2. A line is breadthless length. From these definitions of the point and the line, he derives a surface, a plane, an angle and a boundary. And with these simple tools he takes the reader through the construction of geometric figures using straight edge and compass, and uses their method of construction to prove their properties in what is, notwithstanding their mathematical content, a breathtaking demonstration of pure logic.

The final theorem of Book 13 is a proof that there exist only 5 Platonic solids.

## External links

- Entry at Wikipedia