Marek’s disease is a form of cancer of poultry caused by an important herpesvirus (MDV). It continues to be a threat to poultry health and welfare and worldwide losses are estimated to be US$ 1 billion annually. Marek's Disease provides a timely review of the problems of Marek's disease with descriptions of the complex viral life cycle, how MDV targets different types of white blood cells, and details of the virus structure, its genes and proteins. The multiplicity of factors contributing to susceptibility is explored in detail Vaccination - the problems arising from current vaccination strategies and how these can be improved and made sustainable in future The lessons learned in the control of MD over the past 30 years, and how we can use MD as a model for other animal and human diseases is discussed