Is Any New Testament Book Undisputed In Its Authorship? It seems as though every time I turn around, I find that "the majority of scholars" doubt this person wrote this gospel or letter. It seems as though no book of the NT is immune to this doubting and disputation. Doubting every single one of the books seems a bit beyond the pail to me, and suggests a real bias against giving validity to the new testament.

Is there a new testament book or letter whose authorship and date are undisputed and accepted? If not, which one has the strongest argument for its authenticity?
This is a good question, and I think there are several things to consider.

Straightaway, you should keep in mind that phrases like “the majority of scholars” or “many scholars”—which are encountered everywhere in Biblical scholarship—would be rejected even by Wikipedia as weasel words. 

Next, as the commenter observes, everything can be questioned; and given that academics need publications and presentations in order to be employed, everything surely has been questioned by now. (See the Wikipedia article on the authorship of the Pauline epistles—even the “Undisputed epistles” are disputed; they give citations!)

But the final thing to ask is what kinds of arguments can be constructed either way. What does it mean, for instance, to dispute the authorship of Jude? There is nothing to compare it to; the same goes for Matthew and Mark, for example.

The name “Paul” has more books associated with it, and Paul is prominent in Acts, and is mentioned in 2 Peter 3:16. But even then, one can only ask whether the fourteen letters bearing Paul's name were written by the same person or different people. Perhaps I believe that the Pauline epistles were written by two different people. But I can never know which person had the Damascus Road experience. (Wikipedia lists Ephesians as disputed, but perhaps Ephesians is the only letter actually written by Paul, and all the others are forgeries. It's just not possible to argue one way or the other.)

A final note is that it's very difficult to make a convincing argument about authorship. Here is a passage from Richard Hays's The Moral Vision of the New Testament:


  New Testament scholars are sometimes oddly resistant to the idea that
  Paul could have developed or even declined as a theological thinker.
  When the topic of pseudonymous composition arises, I like to ask my
  students whether all those albums issued under the name of Bob Dylan
  for the last fifteen years can possibly be the work of the same person
  who performed “Highway 61 Revisited.