This book is part of the Lift Off! series for young readers which have been developed and written to be used as part of the National Curriculum. The books are designed to develop understanding and to stimulate the enquiring mind - with each book investigating and explaining an aspect of the world in which we live. This book on what is up in the sky introduces the subject of air and atmosphere, starting with air as essential for all living things and moving on to hot air balloons, flight and space. Other books in this series include The Weather and The Water Cycle.