II John is a book in the New Testament. It is one of the five biblical books which consists of a single chapter in the modern Bible, and is only 298 words long. It takes less than 3 minutes to read aloud.
This letter was probably written in about 90 A.D. from Ephesus. Some speculate that II John was a sort of cover letter for I John, while others say the two were clearly meant for different audiences. II John apparently was authored by the same person who wrote III John, because he identified himself as "the Elder" in each (but not in I John).
The author identifies himself as John, historically considered to be the Apostle John, who also wrote the Gospel of John along with I John, III John and the Book of Revelation. Liberal theologians disagree, conceding only that all three epistles were likely written by the same person.
The use of the phrase "eternal life" occurs repeatedly in the Gospel of John and 1 John, but not in II John or III John, which suggests that the authorship of the first two were the same, but the authorship of the latter two may have been different. However, II John and III John are both every short, only about 10% the length of I John, so conclusions about authorship are difficult to make.