**1. ISBN Overview and History:** – The SBN system transitioned to the 10-digit ISBN format in 1970. – Each edition of a publication requires a unique ISBN. – The ISBN structure consists of a 13-digit code since January 2007. – The International ISBN Agency manages global ISBN registration. – The US had over 3.9 million registered ISBNs in 2020. **2. ISBN Issuing Process and Structure:** – ISBNs are country-specific and issued by national agencies. – Registration groups are primarily allocated within the 978 prefix element. – ISBNs consist of prefix, registration group, registrant, publication, and check digit. – The structure of ISBNs is detailed in the International ISBN Agency’s manual. – ISBNs are obtained by publishers from the respective national agencies. **3. ISBN Check Digits and Calculations:** – ISBN-10 check digit ranges from 0 to 10. – ISBN-10 check digit calculation ensures a multiple of 11. – ISBN-13 check digit method differs from ISBN-10. – ISBN-13 check digit calculation involves multiplying digits by 1 or 3. – The check digit calculation method is the same for both ISBN-13 and EAN-13. **4. ISBN Database and Conversion:** – The Global Register of Publishers contains ISBN details. – ISBN-10 to ISBN-13 conversion involves adding 978 at the beginning. – The conversion process ensures compatibility with the ISBN-13 system. – The ISBN database is freely searchable online. – Different publishers may have varying registrant elements. **5. ISBN Usage, eISBN, and Global Impact:** – Publishers and libraries have varying policies on ISBN correspondence. – An ISBN is required for listing a book on Amazon. – Each digital format of a book must have a unique ISBN. – ISBN plays a crucial role in the global publishing industry. – ISBNs contribute to the accessibility and dissemination of knowledge.