Human beings are famously prone to error, and proof-readers are, after all, only human. But who picks up the errors a proof-reader misses? John D. Barrow challenges readers to estimate the errors that aren't found from the errors that are.

Early in our mathematical careers, we are introduced to prime numbers. These special integers, which possess no divisors other than themselves and 1, are the building blocks for all the integers. Thus an understanding of the properties of primes, including where to find them, is an essential part of number theory, and any serious discussion of prime numbers will inevitably lead to what is arguably mathematics' greatest unsolved problem: The Riemann Hypothesis.

It seems amazing that the universe could be characterised by a mere six numbers, yet, according to Astronomer Royal Martin Rees, this is the case. He makes an excellent case for the necessity of these numbers, though he does not show that they are the only numbers we need.

Bill Bryson - he's a travel writer isn't he? He goes places and writes about them, tells amusing anecdotes about things he sees and people he meets, making his readers laugh at the same time as teaching them something about the places he visits?

The Code Book on CD-ROM, by author Simon Singh and designer Nick Mee, is the interactive version of the best-selling book of the same title. Singh has already shown in The Code Book and Fermat's Last Theorem that he is an excellent communicator, able to explain complex ideas without using obscure jargon. But while the main achievement of The Code Book is to make codes and ciphers intelligible to everybody, the CD goes further and allows you to become a code builder and code breaker yourself. You will find yourself first turning into a code builder, fearful of being cracked, and then into a dedicated code breaker, following tips on how to crack the ciphers.

More milk with your tea, or is that tea with your milk?

Wen Quek works for an award-winning architectural cooperative based in London. Recently, she worked on the new library at the University of Cambridge's Centre for Mathematical Sciences. As she tells Plus, Wen sees many parallels between mathematics and architecture.

The number chosen by the England captain for his Real Madrid shirt is rich in mysterious connotations. But mathematician Marcus du Sautoy backs a new theory to explain why Beckham has plumped for number 23.

In the first of a new series 'Imaging Maths', Plus takes an illustrated tour of an extraordinary geometric construction: the Klein bottle.

The 2003 Dirac Lecturer, distinguished physicist Freeman Dyson, tells Plus why he is an optimist, what makes life interesting and why old-fashioned maths is what you need for physics.