Guy asks if I have art books.
"What kind?" I ask, cheerfully.
He looks at me in disgust, and say, "Never mind."
Now see I get people ask for art books all the time and most of the time they are talking about 'How To'.
If not, they are asking for Mainstream history of art books, and if not that then books about Classic art and if not that then about Modern Art, and if not that then book with pulp or pop art and if not that they might be looking for individual artists like Van Gogh and if not that art books about art movements like Art Nouveau or Pre-Rahpaelite and if not then art books from Asia, especially Japan or they could be looking for books with Poster art from the 60's or they could be looking for ...well, you get the picture.
I've got a little of all of the above, and specialize in "fantastic" art -- not necessarily fantasy art, but art with a fantastic element: street art, for instance, urban, Gothic, tattoo, or illustrative, or designer art.
It's not beyond possibilities they could be looking for fantasy art or comic art or pop-ups.
So, "What kind" seems like a basic question.