With the credit crunch dominating the news, columnists have been wailing about "chaos in the markets", and "turbulent" share prices. But what does move the markets? Are they deterministic, or a result of chance? Colva Roney-Dougal explores the maths, from chaos to group theory.

Actuarial science began as the place where two branches of mathematics meet: compound interest and observed mortality statistics. Financial planning for the future is therefore rooted firmly in the past. John Webb takes us through some of the mathematics involved, introducing us to some of the colourful characters who led the way.