The Lives of the Caesars include the biographies of Julius Caesar and the eleven subsequent emperors: Augustus, Tiberius, Gaius Caligula, Claudius, Nero, Galba, Otho, Vitelius, Vespasian, Titus, Domitian. Suetonius composed his material from a variety of sources, without much concern for their reliability. His biographies consist the ancestry and career of each emperor in turn; however, his interest is not so much analytical or historical, but anecdotal and salacious which gives rise to a lively and provocative succession of portraits.
The account of Julius Caesar does not simply mention his crossing of the Rubicon and his assassination, but draws attention to his dark piercing eyes and attempts to conceal his baldness. The Live of Caligula presents a vivid picture of the emperor's grotesque appearance, his waywardness, and his insane cruelties. The format and style of Suetonius' Lives of the Caesars was to set the tone for biography throughout western literature - his work remains thoroughly readable and full of interest.