Aims : To present the 4th edition of the WHO classification of tumours of the lung. It covers clinical, radiological, macroscopic, histological, immunohistochemical, molecular pathological, and genetic aspects of the different tumour types. The features of the main tumour types will be presented by eminent European pathologists who were co-authors of this new classification: adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumours.