Recent outbreaks of a novel avian influenza A virus (H5N1) in Asia, Africa and Europe were a chilling reminder that another human pandemic may occur any time. Such a world-wide outbreak will cause intense human suffering, disruption of social systems, major economic losses, and greatly burden health care services. Several pandemics during the last century, like the 'Spanish flu' (1918), the 'Asian flu' (1957), the 'Hong Kong flu' (1968) and SARS (2003) prompted health care authorities for preparedness planning. This book describes these recent incidents and emphasises the need for more structured planning and preparation for medical emergencies such as emerging infectious disease outbreaks.