There are several steps to the publishing of your book, once you have the content and photos in place, and the indexing accomplished. You will need to think some about how many copies you want to print, what size pages in your book, and whether you want your product to be bound hardcover or perfect binding (softcover).
You also want to think ahead as to where you want your books to ultimately reside. Do you really only want a few family members to hold copies, or should your book be added to a genealogical collection in a public library? A few libraries may purchase your work; most will be pleased to accept a copy of your book as a donation.
In order to simplify and facilitate cataloging of your book in a library, there are two unique reference numbers that you can obtain.
Library of Congress
One of your goals should be to see your Family History or Genealogy book in the national collection at the Library of Congress (LOC). For this, you should apply for a Preassigned Control Number from the LOC. You can accomplish this task online at any time; however, having the Control Number does not guarantee your book will be entered into the LOC. Nevertheless, it is a required step, costs no money, and can be completed at any time. Essentially, you will need to enter the Title and Subtitle of your book, the authors or compilers, and your contact information, including your email address. You will be asked to affirm that you will submit a ‘best copy’ of your book to the LOC when you have completed your printing and publishing. You can read more about this program here.
The International Standard Book Number is not required for publication or for entry to any library – but it does add a certain cachet and aura of legitimacy to your work. And if you are part of a group, it does not have to be expensive.
In the not-that-remote past, ISBNs were free. That is no longer the case. For publications in the United States, R. Bowker has the contract to sell and register ISBNs. If you want only one ISBN, or 1000 ISBNs, you go through the same process with Bowker: essentially, you register yourself as a Publishing Company. The details are at Bowker.com where you can find a triage of instructions for an Author, a Publisher, and for Retailers. For the purpose of this SIG, you are (or will be) a Publisher.
When you register as a Publisher, you just decide if you want to purchase a single ISBN for $125, a package of 10 ISBNs for $295, or perhaps a package of 100 ISBNs for $500. As you see, the per-item price drops sharply if you are willing to purchase a larger block of numbers. Since there is no expiration date on the numbers, it will behoove you to obtain a larger block. Visit Bowker.com to learn more.