What type of things did Hemmingway mostly write about?

Question

and what are his best books?

Answer 1

Many of his works were actually semi-autobiographical, drawing from his experiences in WWI, his alcoholism, his appreciation of latino culture, etc.

By and large, his best book is A Farewell to Arms, which is perhaps also the best WWI book ever written. He also won the Pulitzer Prize for The Old Man and the Sea, which is very entertaining if you can understand the symbolism.

Answer 2

s*x & DEATH!

That's what all the good books are about.  Hemingway also puts in a lot of things that also appeal to men like war, hunting, fishing, smuggling, babes, getting drunk, and why boys carry knives while hitch-hiking.