[warning, the following may contain errors]deuterocanonical books means "second canon" in greek. it usually means the parts of the bible that are only used by some christian churches (mostly roman catholic and orthodox). the books only exist in greek language manuscripts that were written by the jewish people living in greek speaking areas of the mediterranean sea between 250 and 50 bc, as were all of the books of the old testament. it was not until circa 900 ad that the old testament as known in jewish and protestant religions was written in hebrew and limited to the current so-called "canons".[citation needed, see dead sea scrolls]