Billy and the Minpins - Roald Dahl

Billy's mum says he must never go out through the garden gate and explore the dark forest beyond. So, one day, that's exactly what he does! 

There he meets the Minpins, tiny tree-dwelling people whose children are the size of matchsticks. They live in fear of the terrible, galloping GRUNCHER. Will it gobble Billy too - or can he find a way to defeat the hungry beast?