The Epistles are real letters, not treatises by a theological professor, nor literary productions like the Epistles of Seneca. Each was written with reference to a definite situation; they are messages which would have been delivered orally had the Apostle been present. Several letters have certainly been lost; and St. Paul would probably not have cared much to preserve them. There is no evidence that he ever thought of adding to the Canon of Scripture by his correspondence. The Author of Acts seems not to have read any of the letters. This view of the Epistles has rehabilitated some of them, which were regarded as spurious by the Tuebingen school and their successors. The question which we now ask when the authenticity of an Epistle is doubted is, Do we find the same man? not, Do we find the same system? There is, properly speaking, no system in St. Paul's theology, and there is a singularly rapid development of thought. The 'Pastoral Epistles' are probably not genuine, though the defence of them is not quite a desperate undertaking. Of the rest, the weight of evidence is slightly against the Pauline authorship of Ephesians, the vocabulary of which differs considerably from that of the undoubted Epistles; and the short letter called 2 Thessalonians is open to some suspicion. The genuineness of Ephesians is not of great importance to the student of Pauline theology, unless the closely allied Epistle to the Colossians is also rejected; and there has been a remarkable return of confidence in the Pauline authorship of this letter. All the other Epistles seem to be firmly established.