The definitive guide to Hypnic Headache, based upon a systematic review of all available published cases. This rare headache disrupts the lives of over 250,000 people worldwide, and Dr Forbes explains all that is known in his own easy-to-read style. This unique book contains 18 tables and illustrations, and a full list of 69 references. The book provides instructions on how to keep up to date with latest developments in Hypnic Headache and how to contribute to research into this rare headache.