Saying "tą książkę" here would be making one of the most common mistakes that natives do. But nevertheless, it's a mistake.
You can think of the phrase "this book" as a whole. When Accusative is needed, then it is needed for both these words. When Instrumental is needed - both words again. "tą książkę" would for some reason use an Instrumental pronoun with an Accusative noun. A mistake.
I think the easier way to think about it is actually very simple: if the form of the noun ends with -ę (Accusative), so does the pronoun. If it ends with -ą (Instrumental), so does the pronoun. I mean, I'm talking about feminine nouns only here, of course, so obviously pronoun = a form of 'ta'.
Edit at least two years later: actually "tę" and "tą" are determiners. The feminine pronouns (possessives) end in -ą both in Accusative and Instrumental, so do adjectives.
How would you say "Did you read THAT book"?
Would you say "Czytałaś tamtę książkę?" or "Czytałaś tamtą książkę?" (the latter being my choice). It seems to me that there is an obvious inconsistency here! The demonstrative pronoun "ta" becomes "tę" in the accusative and the demonstrative pronoun "tamta" becomes "tamtą" in the accusative!
Well, it is possible that it means "Were you reading this book?" (Last night, when you said you're going to read, did you choose 'this book' or another one?), but most probably it's something different.
With such verbs as "to read", the perfective/imperfective distinction in the Past Tense usually implies something different than the basic notion of finishing/not finishing.
So perfective "Przeczytałaś tę książkę?" sounds as if I knew you were reading this book, that you were supposed to read it, and I'm asking if you finished it.
Imperfective "Czytałaś tę książkę?" is most probably "Do you know this book? Did you, by any chance, read it?". So I have no clue if you have read this book, if you have even heard about it, but if the answer is positive, then you almost certainly read it whole. "Tak, oczywiście, że czytałem Harry'ego Pottera" = "Yes, of course that I read Harry Potter".