The 2007 WHO Classification of Tumours of the Central Nervous System introduces several new entities and variants, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma, and spindle cell oncocytoma of the adenohypophysis. These entities were added based on evidence of different age distribution, location, genetic profile, or clinical behavior. The classification also includes histological variants such as pilomyxoid astrocytoma, anaplastic medulloblastoma, and medulloblastoma with extensive nodularity. The WHO grading scheme and genetic profiles were updated, and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes. The classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from over 70 experts. The classification is accompanied by a concise commentary on the clinico-pathological characteristics of each tumour type. The 2007 WHO classification is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities worldwide. The classification includes new entities, variants, and patterns, and provides ICD-O codes for each. The classification also includes new variants such as small cell glioblastoma and glioblastoma with oligodendroglioma component. The classification emphasizes the importance of histological grading and the biological behavior of tumours, and provides a grading system for astrocytic tumours. The classification also discusses the prognostic significance of WHO grade and the importance of genetic and histological features in the diagnosis and treatment of brain tumours. The classification is a comprehensive and updated guide for the diagnosis and classification of brain tumours.The 2007 WHO Classification of Tumours of the Central Nervous System introduces several new entities and variants, including angiocentric glioma, papillary glioneuronal tumour, rosette-forming glioneuronal tumour of the fourth ventricle, papillary tumour of the pineal region, pituicytoma, and spindle cell oncocytoma of the adenohypophysis. These entities were added based on evidence of different age distribution, location, genetic profile, or clinical behavior. The classification also includes histological variants such as pilomyxoid astrocytoma, anaplastic medulloblastoma, and medulloblastoma with extensive nodularity. The WHO grading scheme and genetic profiles were updated, and the rhabdoid tumour predisposition syndrome was added to the list of familial tumour syndromes. The classification is based on the consensus of an international Working Group of 25 pathologists and geneticists, as well as contributions from over 70 experts. The classification is accompanied by a concise commentary on the clinico-pathological characteristics of each tumour type. The 2007 WHO classification is presented as the standard for the definition of brain tumours to the clinical oncology and cancer research communities worldwide. The classification includes new entities, variants, and patterns, and provides ICD-O codes for each. The classification also includes new variants such as small cell glioblastoma and glioblastoma with oligodendroglioma component. The classification emphasizes the importance of histological grading and the biological behavior of tumours, and provides a grading system for astrocytic tumours. The classification also discusses the prognostic significance of WHO grade and the importance of genetic and histological features in the diagnosis and treatment of brain tumours. The classification is a comprehensive and updated guide for the diagnosis and classification of brain tumours.