This book provides essential insights into the current state of knowledge regarding the main aspects of cluster headache and trigeminal autonomic cephalgias. The first chapters focus on classification and clinical features, together with familial and genetic aspects. Relevant animal models and the putative role of key nervous structures as the hypothalamus, brainstem, diencephalon and sphenopalatine ganglion are reviewed.  Evidence gained from key molecules such as CGRP in animals and human headache models are discussed.   The book subsequently presents information on the various aspects of the pathophysiology of trigeminal autonomic cephalalgias for example regarding the implication of the trigeminovascular system and the facial autonomic reflexes of the brainstem. Further, it shares insights from imaging studies including functional magnetic resonance imaging and more advanced techniques, as well as brain stimulation procedures.