Differences between ISSN and ISBN

What is the difference between ISSN and ISBN ? ISSN are assigned to serial publications; ISBN are assigned to monographs ("books"). An ISSN can be assigned to a series of monographs as such; and an ISBN will be assigned to each separate book of the series. ISBN stands for International Standard Book Number. More information can be found at The ISBN system website. ::: http://www.isbn.spk-berlin.de/