there is a novelist called allan massie who has wrote a book on caligula, it paints him in a different light than the usual "madman" one, he has also written books on caesar, augustus and tiberius, they are all very interesting books and stick very closely to the truth
maximus
For a serious treatment from exactly the standpoint Paulinus wished - try Balsdon's Emperor Gaius Pretty old now, I admit, as it was written in the 30s (off the top of my head - not sitting by my bookcase at the mo) but may well still be in print. Sorry if this has been covered before - I've only just joined.