The only time you need an International Standard Book Number (ISBN) is if you intend to have your book sold by multiple third party retailers. The ISBN serves as the catalog reference that book stores can use to check and report sales figures on any given book. If a book doesn’t have an ISBN, most book stores will refuse to sell it. If you are only publishing an ebook online, often the online retailers will assign their own book number to it. Thus, you don’t have to waste using an ISBN on an ebook. But if you are publishing a book in print and you want your sales tracked, you will probably need an ISBN. Without the ISBN, you probably won’t show up in any widely available publications bestsellers lists, such as the New York Times or USA Today. Bookstores have to buy the books t sell. That means t’ve invested capital in the product, and the only way t are going to make money and be able to pay wages and utility bills is if t are able to sell those books. A business exists to make money. If it isn’t making money, it won’t be a business for very long. Even libraries have to buy the books t lend out to readers. Public libraries have very restricted budgets. The are often the last line item in any town budget. So when budget cuts are needed for a town, the libraries usually get the short end of the stick. So when a library buys a book, t have to choose books t know will be popular and be read often. To buy a book that is going to do nothing but sit on a shelf forever is a waste of money. Both bookstores and libraries have the same problem. it is a waste of money to buy a book that is never going to be of interest to a reader. The best way to judge whether a book is going to be sold/borrowed often is to check its sales figures across the country. And the easiest way to do this is to use its unique ISBN and call up those figures in the distribution databases. This way, one can obtain accurate sales results, even in the event that there are multiple books with the same title. (Yes, that does happen.) This is how the bestsellers lists are generated. The newspapers check the sales reports generated and made public by both bookstore chains and by book distributors. Whichever ISBN has sold the most copies this week is this week’s number one bestseller. (Note. different publications may have contracts with different distributors and bookstores. This is why one newspaper may be reporting Book-A as being number one and another newspaper is reporting Book-B is number one.) So, by using the ISBN, you can tell whether Star Wars written by George Lucas is better than Star Wars written by Allen Dean Foster based on which one is selling better than the other. (Yes, this is a joke. If you don’t get it, look it up!) The more popular a book is, the more likely it will be a good read.
If your book has been published in foreign countries, t cannot get a copyright in the countries where you are selling the book to. If you are not sure why this is, you can always contact your publisher. You now have two very different options on how to file a copyright application. Option 1: If you plan on selling your book overseas (including North America, Europe, Australia and Asia) and you are NOT looking to do self-publishing, then you can get permission from the author by paying them. This is extremely expensive but t does protect you from being ripped off, thus you could potentially get more profit that way. However, this option might not cover you in all circumstances. Your book may still violate your national copyright if sold by foreign publishers, and you will not be able to claim any profit since the price might be less.