If I am looking at books and want to go back to a previous page, I can't.  It takes me back to a search page.  (I know I am not making sense.)

If I am searching say, natural history and I get through to the Gs, but I want to go back to the Bs, I can't.  Frustrating!

I'm assuming you mean you have clicked the SEARCH button up top, and are on the BROWSE BY GENRE tab, then you select a subject & sub-subject, and then navigate by the alphabet, and if you navigate above the letter G, you can't get back to B without starting over? If I understand you correctly as I just described, try it again, because I just did this and can do it.

Now, I don't know where Natural History is stored, but I tried several others and they worked  fine. Maybe you need to explain it more? Like where are you searching, do I have that part right? Where is natural history? What is it a sub-genre of?