First off, let me say that if you are looking for new or recently published books or anything hip or trendy then you will hate John King Books. John King Book is first and foremost a used and collectible books dealer. Man does he have a lot of them!
John King Books is located in an old glove factory just west of downtown Detroit on Lafayette (not far from the Post Office). There isn't a whole lot of parking, but there is a small lot to the side of the building and is accessible to customers.
This place probably has more books than the entire Detroit Public Library System. It's huge. All four floors of the factory are stuffed with all sorts of collectible and used books organized in a fairly easy to navigate fashion. No matter what topic, I'm sure you can find at least a dozen books on it. They even had a category for Beanie Baby books, among all things! They have a vast collection of classic novels and textbooks to sort through.
I have never left John King Books without spending at least 30 bucks and getting half a dozen high quality books.