Almost everyone who reads this book will have no difficulty with the following exercise.

Exercise B.1What is the probability that at least one of three ordinary dice show a 1 when they are thrown together?

Who was the first person to find the answer to this question? So far as anyone knows, it was the remarkable doctor, author, mathematician and astrologer Cardano born in 1501.

In his lifetime, Cardano was chiefly famous as a doctor and astrologer. Later he was famous for such sixteenth-century best sellers as De Subtilate Rerum (On The Subtlety of Things) which could be considered one of the first popular science books. The observations and inventions, many due to others, but some his own, that he reported earn him a place in histories of optics, hydrodynamics, geology, engineering and cryptography. In a more traditional vein, he wrote books on Wisdom and Consolation (believed, by some, to be the book Hamlet is reading when interrupted by Polonius).

Today, his claim to remembrance rests on three books. The first and most important was the The Great Art on what we would now call the theory of equations. In 1500, algebra, in the sense that we know it, did not exist and all algebraic arguments had to be expressed verbally.