Why books are not for sale in us?

why some books are written on their cover ';not for sale in united states'; why they don't sell it in us????Why books are not for sale in us?
The printing you have is not marked to be sold within the US. There may be a US edition but it isn't the copy you have.Why books are not for sale in us?
When books are published, complicated contracts detail the sale of the book and who profits as a result.





This has to do with the publisher, the distribution and the bookshops. Contracts are legal documents and have to do with the laws where they are issued.





Let's say a German writer sells his manuscript to a publisher in Germany. The resulting contracts have to do with publishing law there as do the agreements. The books is published and sold in Germany (or wherever) based on those agreements. Since U.S. law is different, the book does not automatically qualify for sale in the U.S. The reverse would also be true.





If these agreements have not been established in the U.S., the book is not eligible for trade in the U.S. If the parties who hold the rights to the book wanted to sell it in the U.S., they could probably work that out. On the other hand, their demands may be such that it is not possible. It's hard to say.





Further, for the most part, a book written, say, in France, would have to be picked up by a U.S. publisher and sent into to U.S. distribution. The publisher would want some assurances that the book indeed would make money.





The ';Harry Potter'; books are a good example. They were published in the UK and also published in the U.S. The covers of the books were different. The UK editions were sold in the UK and the U.S. editions were sold in the U.S. There were other arrangements then made for the sale of the books worldwide. A shipment of HP books published in the is not eligible for sale in the U.S. because of contractural agreements.
It's the particular edition, not the book itself; a different edition may be available in the USA with or without a different preface, etc.