These cheerful little books aimed at preschoolers set out, as the series subtitle suggests, to give simple answers to the tricky questions young children ask.

The first six cover such topics as Rain, how it is formed and where it goes, Sleep, why we need it, as well as Belly buttons, Shadows, Snails and Waves.

SmartyCat, a smiley white cat, explores his bright and busy world with endearing enthusiasm. Each book ends with a simple joke and an experiment or activity to be done with a little adult help.