is Volume 7 in the 5th edition of the WHO series on the classification of human tumours. This series (also known as the WHO Blue Books) is regarded as the gold standard for the diagnosis of tumours and comprises a unique synthesis of histopathological diagnosis with digital and molecular pathology. These authoritative and concise reference books provide indispensable international standards for anyone involved in the care of patients with cancer or in cancer research, underpinning individual patient treatment as well as research into all aspects of cancer causation, prevention, therapy, and education. The 5th edition, guided by the WHO Classification of Tumours Editorial Board, will establish a single coherent cancer classification presented across a collection of individual volumes organized on the basis of anatomical site (digestive system, breast, soft tissue and bone, etc.) and structured in a systematic manner, with each tumour type listed within a taxonomic classification: site, category, family (class), type, and subtype. In each volume, the entities are now listed from benign to malignant and are described under an updated set of headings, including histopathology, diagnostic molecular pathology, staging, and easy-to-read essential and desirable diagnostic criteria.