ISBN is probably one of the best known standards in the world - the 13 digit number printed on the back of a book, perhaps even represented as a bar code, is a familiar sight to many.

ISBN has also been very widely adopted - more than 200 countries and territories recognise and use the ISBN. 

As an International Standard, it is very important that there are clearly established lines of responsibility and governance. The various levels of responsibility help to make the ISBN system robust and also to instil confidence in its use.