(This is abbreviated text from The Global Indie Author.) If you elect to use the ISBN system, and to purchase your own numbers, you do this before you put your book on the market, as you must include the number on your copyright page. In some countries the ISBN agency and national registry are one and the same — in Canada, they are combined into Library and Archives Canada — while in others they are distinct agencies: in the U.S., Bowker is the ISBN agency, while the Library of Congress Read More …