( by Jonathan Hoover )
Have a look at the following screenshot:
the above formula will give you all the columns mentioned by you in which there is First Genre which you can mention in Cell B1 and Sub Genre which you can mention in Cell B2.
I have set Data Validation in Cells B1 and B2, which will map data in 'Books'!D:D and 'Books'!E:E respectively.
I hope the above solution will help you, and if you need more help then please do comment below on this blog itself, I will try to help you out.