Reading from a preface with a decidedly less orthodox viewpoint on the matter. (i.e. the New American Bible created by those eminent scholars widely considered to be the successors of the Apostles themselves)
From the late second century to the nineteenth, Pauline authorship of the three Pastoral Epistles went unchallenged. Since then, the attribution of these letters to Paul has been questioned.
So tradition goes to Paul, and the age that invented questioning every obvious thing was the first to question their authenticity.
Most scholars are convinced that Paul could not have been responsible for the vocabulary and style, the concept of church organization, or the theological expressions found in these letters.
And whoops, they decided they weren't authentic because they were different.
A second group believes, on the basis of statistical evidence, that the vocabulary and style are Pauline, even if at first sight the contrary seems to be the case. They state that the concept of church organization in the letters is not as advanced as the questioners of Pauline authorship hold since the notion of hierarchical order in a religious community existed in Israel before the time of Christ, as evidenced in the Dead Sea Scrolls. Finally, this group sees affinities between the theological thought of the Pastorals and that of the unquestionably genuine letters of Paul.
But on second thought, they don't seem to be contradicting each other, so maybe someone can write differently when they're writing to different people over the course of ones lifetime?
You can that introduction yourself, but it goes on to suggest two other ideas about the authenticity of the letters, whether the were written by a secretary, which isn't particularly novel considering Jeremiah and Peter. Or that they were compiled from fragments of Paul's writing and added to and redacted over time, which isn't novel either considering Job, Esther and Daniel.
So, 3 out of 4 groups of scholars say Paul and the majority of salvation history is with Paul writing the letters and regardless, most Christians believe it is the inspiration of the Holy Spirit permeating the entire Bible regardless whose hand marked the papyri.