Who wrote the Catholic version of the Bible?

It comes from the same source and most of it is the same. Genesis, Exodus, Psalms, Isaiah, and all of the other books that we have in the Protestant Old Testament are in the Catholic bible. They are in the same form and contain the same words, additionally The New Testament is identical in both bibles. The difference comes in the books that are called the Apocrypha (Which if I remember right, simply meaning "extra writings") these are a group of books found in Catholic Bibles, but not in the Protestant bible. If you're interested in where these books came from, see below.

These are books that are not contained in the Protestant bibles. Basically what happened is that about 250-200 BC the Israelite people had gotten to the point where they were speaking Greek & Aramaic and few of them spoke Hebrew anymore. So a group of Jewish scholars got together and translated the Old Testament into Greek. At this time, the books of the Old Testament had not been 100% fixed, so they translated several other writings that were of importance to them culturally and religiously, but were probably not to be considered the Word of God, either because they were written to late in History or because they contained teachings that contradicted teachings in Moses, or both. This Greek version of the Old Testament became the bible that Jesus would have read and that all of the Apostles would have read. It's interesting to note, however, that in all of the New Testament there are well over 300 quotations from the Old Testament and only one possible allusion to one of these "extra" books, meaning that it Christian's from day one seemed to understand that these books weren't actually Inspired Scripture. The Dead Sea Scrolls also contain very little of the Apocryphal books as well, again a sign that Jewish people as early as 150-200 understood that these weren't inspired by God. Anyway, by the time Jerome got around to translating the bible into Latin, most of the Church didn't really understand all of this Although Jerome and many other Church Fathers (Augustine, athansias & Ambrose and many others), although he understood that these were not Scripture, he translated them into Latin b/c so many people in the Church were used to having these books in their bibles. Over the course of the next several hundred years the Catholic Church gradually began to accept these books and when the Protestants broke away in the 1500s it became a way for them to try to de-legitimze the Protestant movement. They issued several statements saying that anyone who did not accept these books as Scripture would go to Hell.