Produced by the World Health Organization (WHO), this handbook is an introduction to the science behind bird flu and the potential for an influenza pandemic. It contains background information including influenza pandemics of the 20th century, general questions about pandemics, the uncertainty surrounding bird flu, the six global pandemic phases identified by the WHO, how antiviral drugs and vaccines work, and how nations can prepare for a pandemic. It also contains an extensive list of WHO regional contacts. The 24-page handbook is regularly updated and is useful as a fact checking reference and background information source for journalists.