Mark Morford provides a lively, succinct and comprehensive survey of the philosophers of the Roman world, from Cato the Censor in 155 BCE to the death of Marcus Aurelius in 180 CE.
Roughly a third of the book (about eighty pages) is devoted to poets who made minimal to nil contributions in philosophy (Lucretius, Horace, Virgil, Lucan). The author gives Epictetus and Marcus Aurelius, respectively, fourteen and ten pages.