The discovery of the structure of DNA

On 25 April 1953, Nature published a letter by Francis Crick and James Watson, at the Cavendish Laboratory, Cambridge, proposing a structure for DNA. This letter marked the beginning of a revolution in biology. Besides Crick and Watson, two other scientists, Rosalind Franklin and Maurice Wilkins, played key roles in the discovery. After sketching the early careers of the four scientists, the present article gives an account of the physics and chemistry involved in the discovery, and the events leading up to it.