Encephalitis means "inflammation of the brain," but it usually refers to brain inflammation caused by a virus. This severe and potentially life-threatening disease is rare. Encephalitis takes two forms, categorised by the two ways that viruses can infect the brain: Primary encephalitis. This occurs when a virus directly invades the brain and spinal cord. It can happen to people at any time of the year (sporadic encephalitis), or it can be part of an outbreak (epidemic encephalitis).* Secondary (post-infectious) encephalitis. This form occurs when a virus first infects another part of the body and secondarily enters the brain. The primary form of the disease is more serious, while the secondary form is more common. This new volume presents important research from around the globe.