If you want to learn about someone's life story, you might head to the nonfiction section and pick up a biography, autobiography, or memoir. While these 3 formats all delve into the subject's personal history, you'll find distinct differences between all 3: Autobiographies: These books are life histories, written by the subject of the book. Because autobiographies offer details about the authors' achievements and life experiences, they are often written later in life. Biographies: Biographies are also life histories, but written by someone else. Biographers use research sources to detail key events that shape their subjects' lives as well as concrete information about things like education, relationships, and work. Memoirs: Memoirs are collections of memories, also written by the subject of the book. The difference between autobiographies and memoirs is the focus. Memoirs go beyond presenting facts to reflect and establish an emotional connection.