A biography is the true story of a person's life, written by someone else. When you read a biography of Abraham Lincoln, you're learning about his childhood in Kentucky, his work as a lawyer, and his presidency during the Civil War, all researched and written by a historian or author who studied his life carefully.

Biographies differ from autobiographies, which people write about their own lives. They also differ from fiction: everything in a biography should be based on real facts, letters, interviews, and historical records. A good biographer acts like a detective, gathering evidence to understand what happened in someone's life and why they made the choices they did.

People write biographies of presidents, scientists, athletes, artists, and anyone whose life offers interesting lessons or stories. You might read a biography of Marie Curie to learn how she discovered radium, or a biography of Jackie Robinson to understand his courage in breaking baseball's color barrier. Libraries organize biographies in their own section, often marked with a “B” or “920” on the spine, making them easy to find when you want to learn about real people who shaped the world.