In Siem Reap you're bound to come across a push cart like this selling English language books. Most are manned by ex-soldiers, some of whom were maimed by land mines.
They're just trying to make ends meet in this impoverished country. They are always on the lookout for tourists to buy their books.
So, if you see them buy a book or two. Most of the titles are actually interesting, and surely there'll be one that will appeal to you.