I know. I went to Barnes and Noble in Baltimore and was directed to a bottom corner of a small section near the magazines. 'We don't have much' was the answer when I enquired. One book on arduinos and no others on hardware or engineering at that level. The section on math next to it wasn't much more varied either.
Haven't been there lately, but I don't think that "for Dummies" is entirely what is there. It isn't a great technical bookstore, but I have seen some good books in the computer science section (even if the books aren't that computer-scientific).