This is one of the best overviews of classical literature, as well as a handy quick reference. "Classical literature" is the convention for Greek and Latin literature starting from Homer in ~700BC to sometime in the late Roman empire. (Rutherford picks 410 AD and Augustine's City of God as his stopping point, which is reasonable since people can't even agree on when the Roman Empire ended these days.) Rutherford contextualizes a huge amount of poetry and prose into a reasonably comprehensible framework in 300 pages. His success is pretty amazing.
Rutherford's division into genres is the smartest move. Rutherford traces each genre chronologically helps fix the general sequence of works in your mind without overwhelming you with too many works at once. So the chapters on Epic, Drama, Rhetoric, and Philosophy each give mostly self-contained chronological overviews of key works, while referencing linkages to other genres. Rutherford admits his divisions are fluid and sometimes arbitrary: the chapter on "History, Biography, and Fiction" is basically three mini-chapters that happen to fall loosely in line chronologically. But this doesn't pose a problem.
Within each genre, Rutherford hits the big names but also many smaller ones as well (some only extant in fragments): his chapter on epic goes over the Epic Cycle, Appollonius, Lucan, Statius, and even Silius, in addition to Homer and Virgil. So rather than just calling out the Great Books, he gives an idea of how trends in literature produced high points and lesser ones, and the cycles of influence and reception that occurred. You can gripe about minor omissions like Nonnus or Sextus Empiricus, but overall he is quite comprehensive.
Rutherford's focus is on literature and rhetoric rather than the history of ideas, and the chapters on philosophy and religion are less satisfying than the rest of the book because there just isn't room to outline the systems of Plato and Aristotle in sufficient detail. Rutherford is content to describe their historical and literary significance before going on to Lucretius and Virgil's Georgics.
Nonetheless, on literature the book is extremely satisfying and the annotated bibliography is rock-solid, giving a handful of works on each genre. He doesn't just go for the latest trends, but calls out important earlier works. He recommends Burckhardt, Dodds, Curtius, and Auerbach, and I'm with him that they're more inspiring than all but a handful of academics today, even if they're sometimes out of date.