Cluster headache affects 0.1 per cent of the population and is a severe form of primary headache. This volume of Frontiers in Headache Research is an up-to-date and comprehensive review of the condition and its related disorders. The book begins with a discussion of the basic circadian biology of the condition followed by an overview of relevant epidemiological studies. Cluster headache is then described in comparison with related disorders, including paroxysmal hemicrania, SUNCT, hemicrania continua and hypnic headache, and the system of classification discussed. The volume then moves on to look at the wealth of basic research into cluster headache, including, animal studies, work on the autonomic nervous system in man, neuropeptide research, studies of biological rhythms, the associated endocrinology, information derived from neuroimaging and the influence of genetic factors. The final sections of the book examine acute treatment, prophylaxis, the potential for surgical treatment and the opportunities for further innovative therapies. The contributing authors are all international specialists in this field.