I, Claudius, by Robert Graves (Vintage Classics, £7.99 in UK)

Personally I have always found Graves's Claudius books rather dull and elementary, but probably I am wrong since they go on appearing in edition after edition (this novel first appeared in 1934). It would be a major irony if Graves, who regarded himself as a major poet and saw novel-writing as little more than pot-boiling, were to be remembered eventually by his historical fiction when his poetry is reduced to one or two anthology pieces. However, I still prefer to read Suetonius and Tacitus in the original, rather than in fictional paraphrases; they are lively enough without adding fancy dress and rather ponderous dialogue.