Originally Posted by JSWolf
Could this Mobi just be an image based eBook instead of text? If so, Calibre is going to be resizing every single page.
I'm beginning to think that this may well be the case. In any event, I've since attempted to open the file itself in Kindle 4 Mac and in Calibre - it causes both to crash. I think I'll simply return it for a refund and purchase a paper edition.