He is almost 13. He is very... interested in the subject of puberty (understandably, of course). Since he was very small, I have always done my best to answer any questions about bodies/relationships etc honestly and in an age-appropriate way, but I think we are getting to the stage where both of us would find it more comfortable if he had a helpful, sensible book to read.
I've looked around online and I'm certainly going to steer him in the direction of Scarlateen and Bish when he's a bit older, but both those sites are a bit advanced for where he is at the moment.
So - anyone with teenagers got any recommendations for a sound, sensible book on the subject of puberty?