In the book Caligula: A Biography, the authors' main purpose is to show a historical account of Caligula's life and reign as emperor of the Roman Empire. The authors consider several ancient writers who chronicled his life and, through their research, attempt to affirm or discredit the many outlandish claims they make. The book begins with accusations from ancient writers such as Seneca, Pliny the Elder, Josephus, and Suetonius who all claim that Caligula suffered from madness. It is clear that the authors do not believe this accusation and throughout the book they attempt to prove their theory. They instead portray him more as an evil genius with ulterior motives for his actions. They note that Suetonius suggests that Caligula committed incest with his sisters, but use the fact that Seneca and Philo of Alexandria do not, as a way to discredit the idea. They begin by telling the story of how Caligula's great-uncle Tiberius was chosen to reign after the passing of Augustus, Caligula's great-grandfather. An account of the family of Caligula me...