"I decided that the gossip test is a good one ... that what you're really interested in is what you gossip about."
Francis Crick was in his early 30s before he perceived he should be a molecular biologist. It was a fortunate insight: within five years he and Jim Watson solved the structure of DNA, the fundamental genetic material. In conversation with Lewis Wolpert of the Middlesex Hospital Medical School, London, Professor Crick reflects on the nature of that momentous discovery - and also on the problem of what you do next.