I never found amazon useful. Few weeks ago I ordered 7 books on amazon. It told me that all books will be delieverd upto the 7th day. I waited upto the 10th day but my books not came. 3 books came in 11th day and remaining upto 13th day. I also found 3 defective books. Not much defective but some pages were torn up. I fell really bad.From then I totally rejected to use amazon.Quality is bad and the delievery time is also not appropriate.