It's the best 2nd hand bookstore I know – concerning variety, specials and the price is ok too. They have a lot of unusual books and I may spend ages there aiming to find another discovery. The owner is an interesting person too, if you manage to see him between the towers of books.
Yeah, it's better to be prepared before going inside: there's a big room from floor to the ceiling full of books, only small trails leading through it. If you just stumble inside you will get lost in the stories and the aim to discover another extraordinary book... if you like this kind of adventure then you're at the right place!