James D. Watson, the molecular biologist who co-discovered the double-helix structure of DNA in 1953, has died at the age of 97. The Nobel laureate shared the 1962 Nobel Prize with Francis Crick and Maurice Wilkins for uncovering the structure that transformed modern genetics. Over his long career, Watson authored influential books, led the Human Genome Project, and mentored a generation of scientists. However, his later years were marred by controversy over racist remarks that led to widespread condemnation and the loss of his honorary positions.