For billions of years, cells have used an ingenious system of storing and processing instructions to make proteins, the molecules that carry out vital functions for the cell. Data is warehoused in DNA molecules, copied into RNA molecules, and then read by a cell's protein synthesis apparatus. It is the genetic code that enables this data transfer to exist. The Genetic Code tracks the key experiments and discoveries that set in motion efforts to crack the code and explores the many ways humans have applied knowledge of the genetic code to alter gene activity. From the engineering of genetically modified plants and animals to the revision of genes in human cells, scientists are modifying cellular processes by manipulating the genetic code, the cell's own language.