The most significant difference between a biography and an autobiography is the author. The prefix "auto" means "self"; therefore, an autobiography means the author is also the subject of the book. He writes his own life story, drawing on his own memories. A biography means someone other than the author is the subject of the book. In this case, the author writes the life story of someone else, drawing on that person's memories. Books about celebrities are frequently biographical because the celebrity rarely writes the book himself.
A biography can be authorized or unauthorized. An authorized biography is written with the permission and input of its subject. An unauthorized biography is written without the permission or input of its subject. The author does his own research to write the biography, which is why unauthorized biographies are more likely to contain errors. An autobiography is not distinguished as authorized or unauthorized. Because the author himself is writing about his own life, he needs no permission.
Both biographies and autobiographies focus on pertinent information such as birth, youth, adulthood, education, career and death. They are typically written to focus on the entire life of the author and the chronology of events. If the book focuses on a particular period or event in a person's life, it is a memoir. While biographies and autobiographies give a panoramic view of an entire life, memoirs focus on themes and are more intimate portrayals of a person's life. Memoirs can be biographical or autobiographical, but biographical memoirs tend to be ghostwritten, which means the subject didn't write it but is given credit for writing it.
Biographies and autobiographies are both classified as nonfiction. However, each of them can be used as the basis for a novel, making it a fictional account based on real life. This is called a biographical or autobiographical novel. The writer exaggerates the truth, changes names and locations and dramatizes events to suit the story. Alternatively, it is possible to write nonfiction using the characteristics of fiction as a literary device. Plot, setting, characterization and point of view are all used to tell a true story.