R.R. Bowker LLC ("Bowker") is an American limited liability company based in New Providence, New Jersey, and incorporated in Delaware. Among other things, Bowker provides bibliographic information on published works to the book trade, including publishers, booksellers, libraries, and individuals; its roots in the industry trace back to 1868. Bowker is the exclusive U.S. agent for issuing International Standard Book Numbers (ISBNs), a universal method of identifying books in print.