No! No! No! The little troll is terribly angry. It's like there's a storm inside him, with lightning shooting out of the sky and thunder rumbling loudly. Yes, that's exactly how he feels: like a rumbling and grumbling troll. A grumbletroll! Eventually his friends get fed up with his yelling and go off to play without him. Will the little troll be able to make up for his bad behaviour and win back the favour of his friends? Grumbletroll serves as a model to help children recognise and learn ways to stop fits of rage that we all struggle with when things don't go our way. AGES: 0 to 6 AUTHORS: Steffi & Michael Gerharz (aprilkind) live with their three children. The idea for the grumbletroll came to them when their youngest daughter was sitting at the breakfast table with her arms folded, sulking and grumbling. Barbara van den Speulhof is a children's book author and director and producer of radio plays for children. After short periods in mechanical engineering and architecture Stephan Pricken studied primary school teaching with a focus on art, and then graphic design.