Book excerpt: This is the third volume in the new World Health Organization series on histological and genetic typing of tumours. Tumours of the haematopoietic and lymphoid tissues are covered. This was a collaborative project of the European Association for Haematolpathology and the Society for Haematopathology and others. The WHO classification is based on the principles defined in the Revised European-American Classification of Lymphoid Neoplasms (REAL) classification. Over 50 pathologists from around the world were involved in the project and proponents of all major lymphoma and leukaemia classifications have agreed to accept the WHO as the standard classification of haematological malignancies. So this classification represents the first true world wide concensus of haematologic malignancies. Colour photographs, magnetic resonance and ultrasound images and CT scans are included.