What is the origin of the Catholic apocrypha?

In the Catholic tradition, several "apocryphal" books are used in addition to the same Old Testament canon used by Protestants. * What is the origin of these books and how do they differ from from the other books? * Do Catholics view them as infallible? * Are they considered to be on the same level with the rest of the Old Testament or do they have some second rate status such as some form of non-divine wisdom literature?