[Ninjalawyer]

I'm going to cheat a bit and name a series rather than one book.

Gene Wolfe's Book of the New Sun series seems little known for how good it is. I'm a scifi fan, and I'd never heard of it until last year. Some digging reveals that a lot of big name authors love it (Gaiman for example), but the series never seems to pop up in conversations about best scifi series.