International Standard Book Number

What is ISBN?

ISBN stands for International Standard Book Number. In 1966 the first standard number was introduced (a 9 digit number), which became a 10 digit number in 1970 and recently, in 2007, became a 13 digit EAN number.
An ISBN number is assigned to each edition of a book. The modern, 13 digit code, consists of five parts:
1. A standard prefix of 978 or 979
2. A group identifier
3. The publisher code
4. The item number 5. A check digit

Do I need an ISBN?

If you are producing your book to be generally available to the public (even a circumscribed public, like the members of a club or association), whether it is your intention to sell it, loan it, licence it, or simply give it away, you are regarded as having published the book. As soon as you publish a book, you require an ISBN number. So, unless it is your intention to produce a very few copies which are to be given only to people very close to you, it is advisable to get an ISBN number.
However, once you have an ISBN number, you also have certain obligations. In terms of the Legal Deposit Act (54 of 1997), you are required to lodge copies of your book with various legal depositories. As a rule of thumb, you will need to lodge one book if you print between 20 and 99 copies, and five books if you print 100 or more copies. You can get full details here.