Problem of authorship in the New Testament
Biblical scholars today think that several of Paul the Apostle’s epistles in the New Testament (e.g. Letter to the Hebrews) were probably not written by him. In recent apologetics videos that I have been watching, Muslims term these letters “forgeries.” To a modern reader of the Bible, this definitely poses a problem. Do we consider the books of the New Testament that have been misattributed (and phrases that have been added by later authors, such as 1 John 5:7) forgeries? If not, how are we to reconcile our modern quest for truth with the apparently lax historical standards of some New Testament authors?
In other words, are these books and passages in question truly problematic? Yes and no, I think. They are troublesome from the perspective of our modern requirements for truth and transparency, which train us to frown upon individuals in the past who have attributed works to Paul that were not written by him (and added passages to other books that were not originally there). But there is more to the story. Literary genres in the past were different than they are today. Attributing a work to a known figure may have been a form of humility that ascribed respect to the named person while minimizing the author’s own importance.
But I’d like to propose a greater point. Christians believe that the books of the New Testament were inspired by the Holy Spirit. The same (perhaps even more so) can be said for the compilers of the biblical canon. Did the compilers of the canon know that some of the letters attributed to Paul (and other added passages) were not authentic? I would have to study the history of the Ecumenical Councils to answer that question.
But even those that believe in sola scriptura must admit the important role of Church tradition in our understanding of the Bible, because the compilers of the canon were the ones that defined what became part of the New Testament and what did not. For a Christian to doubt that the Holy Spirit influenced the compilation of the New Testament canon would mean to question the value of the New Testament itself (for why does one then consider those books inspired?). Anyone is free to think and question these things as they like, of course, but I’m just trying to point out what I perceive as a logical train of thought.
I think there is a certain amount of intellectual maturity that one must have to study the Bible seriously. I don’t mean this as a prerequisite for reading the Bible — anyone can read it and learn something valuable. But to truly deal with problems of authorship and tradition such as those mentioned above requires a sophisticated approach that combines knowledge of literature and history. Personally, I’m deficient on all counts, but I’m trying to learn.
HistoryJournal.org 
Good points Alex. For a good primer on the formation of the canon, check out Bruce Metzger’s book: The Canon of the New Testament: Its Origin, Development, and Significance. It’s a bit dated, but solid. I don’t remember Metzger going much into the authorship of the books, however, except for how doubts about such influenced their reception in the canon — e.g. ancient authors offered different ideas about the authorship of Hebrews (the text itself doesn’t make any claims) and many also doubted the attribution of some smaller books like 2 Peter and Jude. I don’t know a good one-stop book for the authorship of the books, but any NT intro textbook will discuss it, from various viewpoints based on the confessional and theological position of the author. There is an excellent discussion of pseudonymity in the ancient Christian context in one of the chapters of Charles Stang’s monograph Apophasis and Pseudonymity in Dionysius the Areopagite.
I’m deficient on all counts just as you are and I use the Bible Odessey for the expert opinion on most of this stuff. We are totally reliant on experts for all sorts of information on many important subjects such as climate change, cosmology, evolution , medical advances in genetics etc etc. The experts don’t always agree so we are pushed to accept the consensus or left without any certainty.
We can however take the Bible as presented and measure it against human behaviour and see if it has been effective . Has salvation. Or redemption saved the planet ? brought peace , prevented the rat race for wealth and position . I’m among those who would argue human nature has changed little in the last ten thousand years and maybe not much since the Old stone age. Some point to science and technical advance but in my opinion it has not improved our natures although many now live much longer. A third of the globe still live on $2 per day and in India twenty million have no toilets.