You might want to visit your local library and browse around. Good ol' Mel Bay, for example, has a dozen books on the general subject, including a recent one with a CD. One of the reasons it's hard for me to recommend a single book is that "Country" is even harder to pigeonhole than "Jazz".
For me, Clarence White & Tony Rice sort of define my ideal country guitar sound. But both were mostly influenced by bluegrass, and of course Clancy was a rock star

. Anything by those two will serve you well imo.