International Standard Numbers (ISN) are globally recognised unique identifiers assigned to intellectual outputs such as monographs, journals, serials, materials and music before the final production for public use. Among these numbers are; International Standard Book Number, International Standrd Serial Number, International Name Identifier, International Standard Music Number, International Standard Audiovisual Number, and ISWN. The International Standard Book Number (ISBN) a unique international identifier for monographic publications whioch identifies each book. The International Standard Book Number (ISBN) is not only assigned to printed materials, but to each variation of a book that exists, such as those from different editors, hard cover or paper back etc. Prior to 2007, the International Standard Book Number (ISBN) consisted of ten digits but was changed to thirteen digits in January 2007, and is usually preceded by the letters, "ISBN". It is important to note that, an assigned International Standar Book Number (ISBN) is unique and peculiar to the material it is assigned to, and can never be revised/reassigned. The 13-digit number is divided into five parts of variable lenghts,separated by a hyphen for ease of reading. The first set of numbers usually indicates the country of the publisher as "978" depicts publications from Nigeria. The International Standarsd Book Number (ISBN) is usually printed on the verso of the title page, back cover, the spine of a book, as well as on the e-copy and electronics publications. Apart from creating worldwide awareness of titles, one of the major global advantages of the International Standard Book Number (ISBN) is the facilitation of compilation and updating of book-trade directories and bibliographic datdbases, such as catalogue and books-in-print.The International Standard Serial Number (ISSN) on the other hand is an eight-digiot number that is globally assigned to identify serials and periodicals including magazines, newspapers, journals, pamphlets, etc. The National Library of Nigeria as the Nigeria bibliographioc centre responsible for the issuance of these International Standard Numbers has the responsibility of sensitizing and advising authors, printers, and publishers on the importance and the professional use of these numbers. Authors and publishers can obtain these numbers by visiting any branch of the National Library of Nigeria or through its website: www.nln.gov.ng.