Horace Freeland Judson's monumental history reconstructs the intellectual adventure of molecular biology's founding decades, from the 1930s through the emergence of genetic engineering. Through extensive interviews with the principal scientists—many conducted before their accounts became standardized—Judson captures the excitement of discovery, the fierce competitions, the wrong turns and sudden insights that led to understanding DNA's structure, the genetic code, and protein synthesis. The book provides detailed accounts of how James Watson and Francis Crick solved the double helix, but gives equal attention to figures often marginalized in popular accounts: Rosalind Franklin, whose X-ray crystallography was essential to the discovery; Erwin Chargaff, whose base-pairing rules provided crucial clues; and the many researchers at Cambridge, Caltech, and the Pasteur Institute who built the field. Judson, a journalist with unusual scientific literacy, explains complex biochemistry clearly while preserving the human drama—the personalities, ambitions, and institutional contexts that shaped what questions got asked and how credit was assigned. His account of the race to crack the genetic code reads like a thriller, with multiple laboratories pursuing different strategies and the solution emerging from unexpected directions. The book's length allows for the kind of detail that reveals how science actually works: not as a linear progression but as a social process of argument, replication, and gradual consensus. This remains the definitive lay history of one of the twentieth century's greatest scientific achievements.