Titus was Paul's first assistant, and served Paul during most of his ministry. He was instrumental in Paul's dealings and communications with the problematic Corinthian church. He explains key portions of Second Corinthians.
Scripture References: 2 Corinthians
Tertius was the scribe for Paul when he wrote Romans. He explains some of the background of the writing of the letter and tells of some of the key portions of its first eight chapters.
Scripture References: Romans 1-8
Phoebe was an influential woman in the early Christian movement. She talks about the last half of the book of Romans, with special emphasis on Chapter 12.
Scripture References: Romans 9-16
Tychicus was one of Paul's special helpers. He delivered several of Paul's letters, including Ephesisans. He explains that this letter was written to the entire church in Ephesus, and talks about several key portions of the letter.
Scripture References: Ephesians