Lymphomas and leukemias of the nervous system result in devastating neurological complications and high mortality. These malignancies may arise within the central nervous system or may disseminate to the brain or cerebrospinal fluid from a source elsewhere in the body. Early diagnosis and therapeutic intervention lead to improvement in neurological symptoms and signs and potentially improved survival. The diagnostic evaluation and treatment of lymphoma and leukemia of the nervous system differ from the standard approaches used when the disease is confined outside of the nervous system. Lymphoma and Leukemia of the Nervous System is a comprehensive review of this challenging group of diseases and should be useful for the practicing neurologist, hematologist, oncologist and for any practitioner involved in the management of these patients.