These Apocrypha books come to us from the original publication of the King James bible. It seems its authors didn't know what to do with these books, so they stuck them at the end.
Whether these books are truly apocryphal ("false"), or deuterocanonical ("not really part of cannon") is a matter of perspective. To hundreds of mllions of Christians belonging to the Eastern Orthodox church, the Eastern Catholical Church, and other traditions, these books are Scripture and part of the Bible.
The Wisdom of Ben Gira -- Ecclesiasticus -- was not part of the 1611 King James publication, but it's too good not to be included.
Another gem of the deuterocanon is chapter 14 of the Additions to the Book of Daniel -- there be dragons!.
The Book of Tobit is another interesting story, an autobiography of sorts...