The International Code of Zoological Nomenclature is both a book containing a set of rules and recommendations on the formal naming of animals, and that set itself. Among zoologists. It was first published in 1961, although it has precedents going back to 1842; the present edition is the fourth edition. The Code is issued by the International Commission on Zoological Nomenclature. As the Commission may alter the Code without issuing a new edition of the book, it is not necessarily so that the book contains the actual provision that applies in a particular case.