First a confession: I was one of those kids in high school who thought the English teacher had her head embedded in her nether regions when she talked about symbolism and allusion in literature. I bluffed my way through class, but at the time, I didn't buy into the idea of authors carefully crafting their language to convey messages on multiple levels. Of course, I was quite wrong, and though much of what I read today is light on craft, I've begun to appreciate some of cleverness that goes into good writing.
Foster's book may not entirely change the mind of a doubter, but it is — as advertised — "a lively and entertaining guide" to some of the things that go on beneath the surface of great writing. Foster's tone is jovial; he's the easy-going professor all the freshmen love, and his book reads as if firmly aimed at a high-school AP or college freshman audience. This approach was a bit facile for my taste. I would have preferred a wider range of topics in place of some of the conversational glibness.
Overall though, I'm glad that I read Foster's book. As I read it, I saw connections in the books I've read recently (e.g., Sean Stewart's Dante in Resurrection Man was a Christ figure — falling in the frozen river was his baptism). It's given me some desire to go back and read some of the classics. I actually did pick up Huckleberry Finn straightaway — it's too early to tell if this is a blip or the start of a trend.