Molecular Biologists WATSON & CRICK

On Feb. 28, 1953, Francis Crick walked into the Eagle pub in Cambridge, England, and, as James Watson later recalled, announced that "we had found the secret of life." Actually, they had. That morning, Watson and Crick had figured out the structure of deoxyribonucleic acid, DNA. And that structure--a "double helix" that can "unzip" to make copies of itself--confirmed suspicions that DNA carries life's hereditary information.

Not until decades later, in the age of genetic engineering, would the Promethean power unleashed that day become vivid. But from the beginning, the Watson and Crick story had traces of hubris. As told in...