I can't help you with the Textbook format, but I got the first 6 volumes in Pocket Manga fairly cheap as a special order from my comic shop. As long as they order from a company that uses the Previews catalog, they should be able to hook you up.
On the other hand, I didn't really like the first six books, so beware.
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If you become a monster to put down a monster you've still got a monster running around at the end of the day and have as such not really solved the whole monster problem at all.
On the other hand, I didn't really like the first six books, so beware.
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If you become a monster to put down a monster you've still got a monster running around at the end of the day and have as such not really solved the whole monster problem at all.