I've been wondering about this for some years now. I don't think I have ever seen a single TV commercial for a book. Books aren't physically visual like movies, shows, and video games are, but I think they could still be portrayed in video advertising. The commercial could display something that's representative to the storyline or setting of the book to get people interested. As far as advertisements in general for them I still don't see much of their presence. I don't ever see them on billboards rarely on a poster, none in magazines though the only ones I read are video game related or is something like Source or Ebony, but even in those mags you get advertisements from things that don't anything to do with the magazine's subject matter. Also outside of sites like these I'm not sure if I ever seen a random advertisement on a site for a book. I'm not saying that books are completely absent from TV because I've seen them promoted on stuff like Oprah and the Today Show and majority of those occasions I notice most are buy established celebrities. I think there are some missed opportunities for a lot of authors getting their works recognized if their products aren't being advertised on the most popular media.