You might think that if you collected together a list of naturally-occurring numbers, then as many of them would start with a 1 as with any other digit, but you'd be quite wrong. **Jon Walthoe** explains why Benford's Law says otherwise, and why tax inspectors are taking an interest.

Images based on Lyapunov Exponent fractals are very striking. **Andy Burbanks** explains what Lyapunov Exponents are, what the much misunderstood phenomenon of chaos *really* is, and how you can iterate functions to produce marvellous images of chaos from simple mathematics.

**Eugen Jost** is a Swiss artist whose work is strongly influenced by mathematics. He sent us this Postcard from Italy, telling us about his work and the important roles that nature and numbers play in it.

For millennia, puzzles and paradoxes have forced mathematicians to continually rethink their ideas of what proofs actually are. **Jon Walthoe** explains the tricks involved and how great thinkers like Pythagoras, Newton and Gödel tackled the problems.

David Spaughton and Anton Merlushkin work for Credit Suisse First Boston, where they provide traders in the hectic dealing room with software based on complicated mathematical models of the financial markets. PASS Maths interviewed them at their offices in Canary Wharf in London.