A good book to read before going to Australia, while being in Australia or after having been to Australia is Down Under by Bill Bryson.
I case you don't know Bill Bryson, let me assure you that his writting will have you laughing out loud. He has written several travel books, a couple of books about the English Laguage and a science/history book (A Short History of Nearly Everything). His books make you want to go to the places he descripes (well some of them) or go back to those places, if you have already been there.
For some strange reason some of his books are sold under different titles in USA. I.e "Down Under" has become "In A Sunburnt Country" in USA. It could very well be that it is the other way around, that the title used in USA is the original title. I don't know.
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Excerpt from "Down Under/In A Sunburned Country"