The classification of lymphomas is a real headache. Lymphomas often go by different names in different publications, and while some lymphoma categories are easy to recognise, others are disturbingly prone to subjective variability. Two standard classifications, one predominantly in the US, the other in Europe, have been used and adapted over many years. A third, the REAL Classification, was published in 1993. It built on previous classifications and defines diseases by: morphology; immunology and genetics; clinical presentation and course; normal counterpart in the immune system. The REAL Classification has won many devotees around the world. It is, however, complex and describes a much larger number of disease entities than many care to carry around in their head. This book summarises the classification systems in a format that can be carried around in their pockets.