In the lecture of 48 minutes, entitled "Classification of Headache Disorders" by Dr. Sara Sacco from Carolinas Headache Clinic, USA, the International Classification of Headache Disorders (ICHD-3) is systematically explored. Dr. Sacco introduces the general organization of ICHD-3, highlighting its division into three main parts. The most crucial aspect in diagnosing headache disorders is emphasized to be a thorough understanding of the patient's medical history. Part 1 focuses on primary headaches, covering various types such as migraine (with and without aura), tension-type headaches, and trigeminal autonomic cephalalgias, including cluster headaches and paroxysmal hemicrania. The lecture delves into complications, auras, and other primary headache disorders. Part 2 addresses secondary headaches attributed to trauma, vascular disorders, intracranial hemorrhage, arteritis, and other non-vascular intracranial conditions. Part 3 explores painful cranial neuropathies, facial pain, and other headaches, featuring conditions like occipital neuralgia. Dr. Sacco provides a concise overview of the classification system, aiding in the understanding and diagnosis of diverse headache disorders.