Lymphomas are a heterogeneous group of malignancies that arise from lymphocytes - a disease of the body's cells. Since the first report of lymphoma by Thomas Hodgkin in 1832, lymphomas have been grouped into either Hodgkin's lymphoma or non-Hodgkin's lymphoma (NHL). Lymphoma starts when a lymphocyte changes into an abnormal cell, often forming masses (tumors) in lymph nodes and elsewhere. Because lymph tissue is located throughout the body, lymphoma can begin almost anywhere. It can spread to almost any tissue or organ. The clinical behaviour and manifestations of lymphomas in the head and neck region usually lack specific characteristics that would enable attribution to a specific lymphoma entity without biopsy and histological evidence. In particular, with regard to lymphomas having an aggressive course, immediate histological evidence is crucial for patient management, early treatment initiation and often for the outcome. This book of Lymphoma gives a comprehensive guide to the classification, histopathology, diagnosis and treatment, of patients with the disease and also provide latest developments in the treatment of patients with both Hodgkin and non-Hodgkin lymphoma.