The libraries.--The amount of Assyro-Babylonian literature already known is very large. If all the texts at present in the museums of Europe and America could be published, they would rival in extent the books of the Old Testament. Most of the texts are on tablets of clay and have come from the libraries of Nineveh and Babylonia. Every great Babylonian city had at least one library, and the Assyrian kings established other libraries in their own country in imitation of those of Babylonia. About two-thirds of the library of Nineveh, which was largely the creation of Assur-bani-pal, is now in the British Museum. Scribes were kept constantly at work there copying and re-editing old texts, and sometimes writing new ones. A considerable proportion of the texts was brought from Babylonia: a colophon attached to each tablet usually states from what library the text had originally come. The texts were carefully edited; when there was a lacuna in the original the scribe tells us so, and whether it was old or recent; also if the Babylonian character were one which he did not recognize he confesses that he could not read it. Besides the clay tablets, the libraries contained papyri which have now perished. Varieties of literature.--The texts related to all the branches of knowledge studied at the time. Astronomy and astrology, mathematics, geography, medicine, law, history, religion, and mythology, private and public correspondence, mercantile transactions, political documents, the pseudo-science of omens, lists of beasts, birds, vegetables, and stones, are all represented in it, and last, but not least, philology. The necessity of translating and explaining the Sumerian texts doubtless gave philology so prominent a place. Under the head of philology come interlinear and parallel translations of Sumerian documents, together with commentaries and exercises, reading-books and grammars of the two languages, endless lists of characters with their phonetic values and significations, and numerous vocabularies partly bilingual, partly containing catalogues of Semitic synonyms. The decipherer thus has at his command a most elaborate system for learning the Assyrian and Sumerian languages compiled by the Assyrians themselves. Time after time the signification of a new word is given by its synonym or synonyms in the lexical lists, and words of uncertain meaning in Hebrew have more than once been settled by means of their Assyrian equivalents.