We concluded that they probably run some kind of big automated print-on-demand counterfeiting operation, and have a database of textbook PDFs from several publishers. They probably had the wrong entry in their database for this title, and linked it up with the wrong contents. Perhaps next time you order a small-animal veterinary handbook from Amazon, you'll find it full of block diagrams and transfer functions.

I imagine that if they had printed the correct PDF, I never would have noticed. The book was printed on high-quality paper and well bound.

For what it's worth, this wasn't a cheap purchase.

As far as I can tell, someone printed and hardbound a PDF of the actual book, which is otherwise I guess out of print. It's about the best I could hope to get under the circumstances. So ... there we are.

nearly 700 pages of knots, nice!

Weird.

Even in the US a textbook costs ~$10 to manufacture. The reason prices are so high is that there's a high fixed cost up front to write/edit/typeset/design/market the book, and a small, capped number of readers over which you can hope to amortize those costs.

If publishers need to sell for $200 to break even, you can sell your counterfeit copy as "used" for $50-100/u, and get a 4-900% gross margin because you don't have to waste money on things like developing or marketing the content or paying royalties.