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?

Things They Don't Want You To Know is a field guide for confused parents who are currently custodians of any teenager who's feeling lost, alone, depressed or horny.

I'm not an expert, a psychologist, or even a particularly good person, but I do understand the unique kinds of troubles that come with trying to grow up in the current climate, and I wanted to share what would have helped me, my friends, and everyone else I spoke to while writing this book.

It might be hard to read what I write about self-harming, body piercings, gender confusion, drugs and social media angst. It might involve unpleasant surprises and be occasionally disgusting, but it could also help you to understand and support your kids. They won't thank you, but they might hate you less."