There are two types of brain tumours: primary brain tumours that originate in the brain and metastatic (secondary) brain tumours that originate from cancer cells that have migrated from other parts of the body. Primary brain cancer rarely spreads beyond the central nervous system, and death results from uncontrolled tumour growth within the limited space of the skull. Metastatic brain cancer indicates advanced disease and has a poor prognosis. Primary brain tumours can be cancerous or non-cancerous. Both types take up space in the brain and may cause serious symptoms (e.g., vision or hearing loss) and complications (e.g., stroke). All cancerous brain tumours are life threatening (malignant) because they have an aggressive and invasive nature. A non-cancerous primary brain tumour is life threatening when it compromises vital structures (e.g., an artery). This book brings together the leading research in this dynamic area of research.