In 1859 Bernhard Riemann, a shy German mathematician, wrote an eight-page article, suggesting an answer to a problem that had long puzzled mathematicians. For the next 150 years, the world's mathematicians have longed to confirm the Riemann hypothesis. So great is the interest in its solution that in 2001, an American foundation offered a million-dollar prize to the first person to demonstrate that the hypothesis is correct. Karl Sabbagh's book paints vivid portraits of the mathematicians who spend their days and nights on the race to solve the problem.

Many people would say that the task I am embarking on by writing this book is doomed to failure. For them, it is as if I have chosen to write a book in Arabic in the belief that non-Arabic speakers will find something to enlighten them within its pages. I prefer a different analogy. For me, it will be as if I am describing a remote tribe whose customs and language are unfamiliar to the reader, but whom I understand enough to convey something of their inner and outer lives.

To read anthropologists such as Bronislaw Malinowski on the Magic Gardens of the Trobrianders or Edward Evans- Pritchard on the oracles of the Nuer may, for some people, be so far from their experience or interests that such books might as well be in Arabic. But for others at least, the insights that anthropologists can have into the minds of their subjects are possible to appreciate, whether or not the reader speaks or reads the languages of those tribespeople.