I suggest making the individual book targets inaccessible when you zoom out. At some levels I can't even read them yet clicking on them brings up a detailed box

I suggest making the individual book targets inaccessible when you zoom out. At some levels I can't even read them yet clicking on them brings up a detailed box that covers everything else. You could just do a human readable thumbnail in a corner. Alternatively, you could make a click in certain level zoom into that genre of books. It would also be nice to have a drop down list of categories that could get me to the correct area quickly. This would me like those signs that some stores have posted on the ceiling in the various sections (i.e. Reference, Fiction, Bestsellers...). The zoom out/in method is not generally how I browse my local Borders. It makes me think about going to look at one book and then running up the stairs and staring down to find the next book I want to check out :).