R.R. Bowker Company was named exclusive provider of International Standard Book Numbers (ISBNs) in the United States in 1968 (an awful year, otherwise). Today, the company (now just plain Bowker) is part of ProQuest and still pumping out ISBNs as well as standard bar codes for publisher/bookseller inventory management. And, it offers a range of other publishing services and more. A good company. Bowker does license others to help sell ISBNs, such as Publisher Services. But watch out for nefarious ISBN distributor wannabes.
Your books need ISBNs. Every version, edition, and format needs its own ISBN, which can be purchased one-at-a-time (very expensive) or in lots on a steep discount curve. E-Books don’t require ISBNs. If you are publishing using Amazon CreateSpace, you can get your one-off ISBN from them at no cost at all. Sweet deal.
One of my students created a CreateSpace account and was called by someone from Amazon within minutes and asked for the title of his book. The student wasn’t ready to do anything more at that moment and became worried he had done something wrong, or that it would have been a mistake to mention his book title. If Amazon “had” the title, would they do something with it?
I’m pretty sure the CreateSpace person was just trying to be helpful, but I understand why getting a call when you’re already not quite sure what you’re doing would put you off. I haven’t talked with CreateSpace about this, but feel they probably see many people create accounts, only never to be heard from again. It probably works in some cases to call the future author and encourage them to take a next step or two. In any case, I don’t think Amazon will do anything you wouldn’t want them to do with your title or book description. Now, finish that book! 😉
Is this your first project? Assuming it is, I say, “Keep it simple!” Lucky for us, we can start at the top, as it were, by starting our self-publishing journey in Amazon-land, using Amazon CreateSpace and/or Kindle Direct Publishing. (No promotional fees have been paid, or are likely to.) Why lucky? Because Amazon already sells 65% or so of all e-books and can give you access to just about any market or audience segment…everywhere. So, the tools/platforms I recommend, especially for starters, are CreateSpace and Kindle Direct Publishing.
This doesn’t really answer the question, though, does it? As you already have seen, there are dozens, at least, of tools, platforms, distribution channels, and publishing services providers to choose from. I’m just saying if the leading provider of just about everything is free/cheap and easy to use and you get all its massive marketing machine working for you, why not start there? There’s plenty of time to get deeper into the marketplace and engineer the perfect set of capabilities and resources for you. Whatever you decide, best of luck to ya’!