I just wouldn't get too schematic and compulsive about feeling obliged to read certain kinds of books. Their various essay collections are still available. Peter Levi has written a rambling, old-fashioned history of Greek Literature. Erich Auerbach's first chapter in Mimesis is a classic, comparing the Greek and Biblical ways of storytelling. His book Poets in a Landscape discussed Roman poetry and comes with his own terrific translations of Horace, Catullus, et al.
Most Penguins come with good introductions.
They chose as the best book of the last 1,000 years Lord of the Rings. Your opinion awaited. Thanks for that and all the others we have read and enjoyed on this forum in space. I rather doubt that admirers of Proust or Hermann Broch spend much time voting in online polls. I don't stray into Maryland much.