This definitive work chronicles the epic history of human genetics and the quest to decipher the master-code that defines humanity. Moving chronologically from Gregor Mendel’s pea-plant experiments and Charles Darwin's theories to the horrors of Nazi eugenics and modern CRISPR gene-editing technologies, the narrative explains how our understanding of heredity has transformed. Woven alongside this scientific evolution is the author's deeply personal account of his own family's history with recurring mental illness, exploring how our genes shape our health, choices, and future.