In nonfiction, I'm a big fan of the old school....Belmore Browne (very rare, but one of the best), Andy Russell, Grey Owl, Black Elk, Colonel Whelen, Calvin Rutstrum, Sig Olson, Aldo Leopold, Fred Bear, the Muries, etc. etc. etc.....
In fiction, anything by Bernard Cornwell is gold...just read "The Terror" by Dan Simmons...holy cow...that was a hell of a good book.