Difference between textbooks?

Books have different retail prices all over the world. Particularly textbooks like these one. The only difference is that they are printed in the US or Canada for this continent. The publisher might do other printings in places like Europe so that they are more affordable for the people in those places. If you also notice, books that are sold only sold and printed in the US, contain a ISBN code on the back, (those 10-12 digits under the barcode) and they usually are all different numbers, which can tell you the price of the book. However, for books that are also sold internationally have something like:6000000000. Anyhow, this has nothing to do with your question, but my guess is that they are the same things, just designed for the country of the buyer.