The International Standard Book Number (ISBN) was approved by the Leisure and Cultural Services Department, a Hong Kong government unit, and all of them were approved by the government. The book publishing law of Hong Kong implements the book filing system, that is, the Leisure and Cultural Services Department first verifies the book number with the Hong Kong Publishing House, and each time the book number is limited to 10. After publishing books, the publishing house will select 5 ***50 books from each published book and submit them to the Leisure and Cultural Services Department for registration of books in Hong Kong. After the books are filed, the Leisure and Cultural Services Department will reply the book filing receipt to the publisher. At this time, the publishing house can apply for the next batch of ISBN. Only the book number registered in the book register is the official international book number.