This is an overview of 2 Peter. I almost skipped this overview since we just did the overview of 1 Peter. But this book has a much different focus. While 1 Peter focused on external dangers and hardships (the suffering from the persecution for being Christians), 2 Peter focuses on internal dangers of false teachers. Christianity has fought a two front war from its earliest days: From those who would persecute it from the outside and those who would distort its teachings from the inside.
Who wrote it: Peter, one of the twelve Apostles who followed Jesus during his earthly ministry. Peter was brash and outspoken. He denied Jesus three times the night before the crucifixion of Jesus (just as Jesus predicted he would) but was restored to fellowship later and became a key leader of the early church. Also see the 1 Peter overview
When written: Roughly A.D. 67, about 3 years after 1 Peter was written. Peter was killed for his faith shortly after this was written.
Why was it written: Jesus warned against false teachers, and much of the New Testament carries similar warnings and corrects false teachings. Also see Doctrine Counts.