## Turing Machine

**Stefan Kopieczek**explores his story.

Debate surrounds $25000 prize won by undergraduate for

*solving*universal Turing machine problem**Tom Körner**speculates on the historical reasons why computers were invented when they were.

**Mike Yates**looks at the life and work of wartime code-breaker Alan Turing. Find out what types of numbers we

*can't*count and why there are limits on what can be achieved with Turing machines.