Most of the familiar headache drugs are used to stop a headache attack that is already in progress, or about to begin. However, there is now a growing body of research aimed at developing medications that can be taken on a regular basis to prevent headcahes from starting. These drugs will betargetted at patients whose headaches are frequent or who get their headaches at predicatble times. This book reviews the potential for prophylactic treatment of headache. It provides most of the existing evidence in the field of pharmaco-prophylaxis of migraine and other chronic headaches and maythus, serve as a platform for new initiatives in the field. The book reviews the research into the pharmacological mechanisms involved, the classes of drugs in development and the clinical trials methodology. The editors have gathered together the leading international experts to produce a book that will appeal neurologists caring for headache patients, researchers in the field and those based in the pharmaceutical industry.