Titus is a book in the New Testament. The book's namesake, Titus was a pastor and episcopos in the early church.
Along with I Timothy and II Timothy it is considered one of the Pastoral Epistles (letters written regarding the conduct of church leaders).
The letter itself states that Paul the Apostle is its author, notwithstanding attacks by liberal theologians on its authorship (along with that of the other Pastoral Epistles).
It deals with church leadership (verses 6-9 deal with the qualifications of a bishop, which depending on the denomination is either a separate office or is a synonym for elder or pastor) and other church matters. One of the more commonly quoted verses is 3:10, which discusses how to deal with a heretic (after a first and then a second admonishment he is to be rejected).