Immunotherapy is a medical term defined as treatment of disease by inducing, enhancing, or suppressing an immune response . Immunotherapies are designed to elicit or amplify an immune response and are classified as activation immunotherapies. Immunotherapies designed to reduce, suppress or more appropriately direct an existing immune response, as in cases of autoimmunity or allergy, are classified as suppression immunotherapies. This book presents topical data on immunotherapies including: antifungal immunotherapy; active and specific immunotherapeutical strategies for the prevention and treatment of cancer; allergen immunotherapy; dendritic cell/tumour fusion cell vaccine in cancer therapy; CRLA-4 inhibition in malignant melanoma; and others.