I would be remiss were I not to recommend a writer who has a number of titles available at Amazon and your local bookstore it you ask for them. Tim Campbell has a collection called the Fire-Frost International series which include All's Fair and What Goes Around soon to be followed by about 6 other. International intrigue and suspense. He also has a paranormal sort of romance title, Mourning Melody which is a great read. Another friend, Ian Forsythe has a new release out titled Rose by Another Name which is a historical romance set during and shortly after WWI.

History of the world in 10 1/2 chapters by Julian Barnes. It was the first book I read that really opened my mind to alternative thinking.

Difficult to pick one - Hemingway's the Old Man and the Sea for the sheer grit and human courage. Marquez's A Hundred Years of Solitude for the infinity that magical realism can help you to scale

Mediations- Marcus Aurelius

I own at least 8 copies. I always have one close. Still waiting on an autographed first print..

Sorry, can't limit it to one book and won't be so presumptuous to think others should read it too

I remember the first adult book I ever read when I was eleven y.o. was called 'Did She Fall' by Thorne Smith its really old and i havent re read it since i was about 15 but I do remember feeling really adult - My mum never read much, just those condensed slim womens fiction, but she had a copy of Lady Chatterlys Lover under her bed that I found and read not sure that I got any of the sexual allusions at all but knew it was banned - but again it felt like I was really growing up.
I can't pick a favourite because I'd be here all night wondering which really was the best. My Aunt used to belongto a book club and if she found a book she thought i would like she would save it for me - So maybe its a book called Mostly Murder by Sir Sidney Smith the first pathologist

Dominion and Conquest by Donald Trump

Dang, that’s a tough one. One of my all time favorites that I think anyone can enjoy is The Outsiders. And while that does deal with class differences, I feel like something that addresses ethnicity would be a better selection. Unfortunately I can’t think of one off the top of my head. Perhaps Roots but that might be a bit ambitious for people who don’t enjoy reading. I should really revisit that book....

Stranger in a Strange Land. It's the best argument for Sci-fi as a literary movement.

There are the obivioul ones, but Caleb Carr's The Alienist is a great read and one that anyone might enjoy.