The International Standard Book Number (ISBN) is a unique identifier for books. An ISBN is not mandatory, and does not provide copyright on a work. It is used internationally across the book trade and library sector. Apply for an ISBN ISBN Agency Thorpe-Bowker PO Box 42 Prahran, VIC 3181 Tel: +61 3 6185 0043 Email: myidentifiers@thorpe.com.au Internet: https://www.myidentifiers.com.au/