Fill in the blank — Best non-SF authors and books?

I'm am omnivorous reader, but I'll admit I've slanted my reading toward science fiction for most of my life. When I've branched out, I've discovered amazing works by incredible authors, and I want to keep finding 'em! Since I'm not as tuned in to non-scifi, I was hoping I could ping you folks for some suggestions. 

So do me a favor and fill in these blanks:

"The best non-science fiction author I've ever read is __________________ !"

"The best non-science fiction book I ever read is ____________________ !"

Comment on this post or hit me up on Facebook, Twitter, LinkedIn, or the ever-present carrier pigeon. Can't wait to discover something new!

(p.s. Non-fiction is good too ... I love biographies, histories, business thinking, and personal growth books!)