In 1962 the Nobel Prize for Medicine and Physiology was awarded to Francis H.C. Crick, James D. Watson and Maurice H.F. Wilkins, the three men who, almost a decade earlier, had worked together at Cambridge, merging data from chemistry, physics and biology to solve the structure of DNA - Crick and Watson working to build a hypothetical model that would conform in all its parts to what Wilkins' X-ray pictures had already shown of the molecule. This is a reissue of the classic account of the discovery of the structure of DNA. Watson also tells of the excitement of being a young American scientist in Cambridge - how hw saw the challenge of a great discovery waiting to be made.