I have been told that when opening Google Books from different locations (countries) and using different browsers, it displays different pages from the same book. Can anybody explain me why is this?
For some books, Google doens't have the copyright's holders permission to show the whole content of the book, so they just show a random subset of pages. Maybe, those permissions are also country-dependant, so they are allowed to show a different amount of pages depending on the country.
That's why, in some cases, you can see a "different" subset of the book, as they haven't identified you as the same user that already saw the book (you're using different browsers and or from different countries)