You probably all knew and will think I'm completely backwards for not knowing this, but I just discovered Listmania! on Amazon.
I typed in "books on writing" and "books on writing poetry" into google, and up Listmania came. What a great resource. Basically anyone can create a list of books under a particular category.
There are a number of lists created by people pertaining to writing, which is great news for me...
However, if you too have a recommendation please still comment!