Originally Posted by elemenoP
Because when a US publisher buys the right to publish a book, they might only have the right to sell it "in the US." Other publishers bought the rights to sell that book in other countries. I honestly have no idea how Amazon works in other countries, that's why I ask. When you log in to Amazon.com (is that what you do?), you can see all the books, or only the ones available to you?
Amazon only shows the books with buy buttons that publishers have made available in the specific country (unless you tell them you're somewhere you're not).