The International Classification of Headache Disorders, 3rd edition (beta version) is a comprehensive classification system developed by the Headache Classification Committee of the International Headache Society (IHS). It aims to standardize the diagnosis and classification of headaches, including both primary and secondary headache disorders. The classification includes detailed diagnostic criteria for various types of headaches, such as migraines, tension-type headaches, trigeminal autonomic cephalalgias, and other primary headache disorders. It also covers secondary headaches attributed to various conditions, such as trauma, vascular disorders, infections, and psychiatric disorders. The classification is structured into three main parts: primary headaches, secondary headaches, and other headache disorders. Each category includes specific subtypes and diagnostic criteria. The classification is hierarchical, allowing for varying levels of detail in diagnosis. It emphasizes the importance of using the most specific criteria possible, while also considering the possibility of multiple diagnoses for a single patient. The classification is based on extensive evidence and expert consensus, with a focus on ensuring that diagnostic criteria are supported by published evidence or are intuitively obvious. It is also designed to align with the World Health Organization's International Classification of Diseases (ICD-11), ensuring consistency between the two systems. The classification is intended for use by clinicians and researchers to improve the accuracy and consistency of headache diagnosis and treatment. The classification includes detailed diagnostic criteria for various headache types, such as migraines, tension-type headaches, and trigeminal autonomic cephalalgias. It also includes criteria for secondary headaches attributed to various conditions, such as trauma, vascular disorders, infections, and psychiatric disorders. The classification is accompanied by a detailed table of contents, a preface, and a section on how to use the classification. It is intended to be used by healthcare professionals to improve the diagnosis and management of headache disorders.The International Classification of Headache Disorders, 3rd edition (beta version) is a comprehensive classification system developed by the Headache Classification Committee of the International Headache Society (IHS). It aims to standardize the diagnosis and classification of headaches, including both primary and secondary headache disorders. The classification includes detailed diagnostic criteria for various types of headaches, such as migraines, tension-type headaches, trigeminal autonomic cephalalgias, and other primary headache disorders. It also covers secondary headaches attributed to various conditions, such as trauma, vascular disorders, infections, and psychiatric disorders. The classification is structured into three main parts: primary headaches, secondary headaches, and other headache disorders. Each category includes specific subtypes and diagnostic criteria. The classification is hierarchical, allowing for varying levels of detail in diagnosis. It emphasizes the importance of using the most specific criteria possible, while also considering the possibility of multiple diagnoses for a single patient. The classification is based on extensive evidence and expert consensus, with a focus on ensuring that diagnostic criteria are supported by published evidence or are intuitively obvious. It is also designed to align with the World Health Organization's International Classification of Diseases (ICD-11), ensuring consistency between the two systems. The classification is intended for use by clinicians and researchers to improve the accuracy and consistency of headache diagnosis and treatment. The classification includes detailed diagnostic criteria for various headache types, such as migraines, tension-type headaches, and trigeminal autonomic cephalalgias. It also includes criteria for secondary headaches attributed to various conditions, such as trauma, vascular disorders, infections, and psychiatric disorders. The classification is accompanied by a detailed table of contents, a preface, and a section on how to use the classification. It is intended to be used by healthcare professionals to improve the diagnosis and management of headache disorders.