A field guide for parents about the secret lives of 21st-century teenagers - from relationships to self-harm, from drugs to sexting - and how you can help them and yourself through these turbulent years.

"When I turned into a teenager, I watched my parents panic with questions they were unprepared for: is the computer killing his brain? is he watching porn? are those cuts on his arms? what the hell do we do now?

The child-rearing tactics they'd read about in parenting manuals or learned from their own parents were useless. Anyway, how do you punish someone who's already so miserable?