Amazon has many great books on how the brain works, just type in their search bar what you are interested in and it will give you lots and lots of books that you can click on to read a bit about that book, its index pages and a page or two from the book so you can get the right book that fits you.

the books I read are usually college textbooks I get from college book stores, thats another idea for you, if you have a college near by, go browse in their textbooks anything on the shelves marked for heath or psychology will be where you find books on the brain in these stores.