Keeping Healthy: Why Do I Sleep?

ANGELA ROYSTON has written lots of science books for children, including several series on the human body, health, animals, ecology and space. She grew up in Scotland and now lives in London. Angela enjoys travelling, walking, reading and spending time with her family.

Kristina Routh is a medical doctor and writer, with over 20 years' experience providing medical oversight on a range of projects. She gained a degree in Medicine from the University in Bristol and has worked in the NHS, and as a senior lecturer at the University of Birmingham.