Yes, these two both mean the same :)

Hi Shawn, It's "tę książkę" for the accusative case. ;) (I've hacked the grammar... if a Polish native doesn't answer, I'm more than happy to [un?]verify it through my Polish friends.) As far as I can tell, "this/that" doesn't make a difference.

Oliwia and Andrzej are right. Don't bother, it's a really common mistake and having read what Olivia and Andrzej's answers you already have better understanding of grammar than most Poles :). In most cases the article takes after the last letter in the word. So: "tę książkę", "tę bluzę", "tę gitarę", "tę dziewczynę". However, there are some minor exceptions like: "tę służącą". Don't bother though, they are really rare.

Another important thing : Kupiłem tę książkę. co kupiłem? książkę Uderzył mnie tą książką. czym mnie uderzył? książką As you can see, the meaning is totally different, but it's true that Polish people usually make this mistake.

I would simply describe the difference between "tę książkę" i "tamtą książkę" as this and that book. Simple as that ;)