This book is part of a book series called Need To Know .

This book is aimed at children in secondary school.

There are 56 pages in this book. This book was published 2005 by Capstone Global Library Ltd .

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.