This book is written for children to read with their parents. It is about the 'life' cycle of a virus called Ezzy. Humans are always exposed to viruses, from the common cold to more deadly influenza and coronaviruses which can be a threat to health and life. In this book I try to explain the biology of viruses both in a fun way for children, and also in a more scientific way for adults. On each page I provide a simple version of viral behaviour and there is an appendix at the end of the book which provides scientific detail, and references where you can find further information. Viruses are unusual 'living' things and extremely interesting (to scientists), but need to be understood in their behaviour to prevent their harmful effects.