To add to what I wrote about the deuterocanon, most of them may be relatively unimportant, but not because they are less inspired or less authoritative. Rather, some of them are less important because they have less original or fewer important messages contained within them. However, this is not always the case, nor is it limited to the deuterocanon. For example, 2 Maccabees is the book on which the important Catholic doctrine of Purgatory is based while many canonical prophetic books contain little that is original or relevant. They are still inspired Scripture and authoritative books, but few would say they (or any books in the Bible, for that matter) are as important as the gospels.