James and Francis Crick won the Nobel Prize in 1962 for the discovery of the double helix, the structure of DNA. In this book, James tells the exciting story of this discovery. Penguin Readers are simplified texts designed in association with Longman, the world famous educational publisher, to provide a step-by-step approach to the joys of reading for pleasure. Each book has an introduction and extensive activity material. They are published at seven levels from Easystarts (200 words) to Advanced (3000 words).