This book brings together material on all aspects of immunological tolerance. Basic mechanisms of tolerance are examined in detail, including mechanisms of peripheral T cell tolerance, molecular and genetic mechanisms for maintaining self tolerance, partial T cell activation, and the role of apoptosis in tolerance. Careful consideration is also given to the clinical applications of our understanding of immunological tolerance, with specific chapters dealing with T cell activation during tumour therapy, antiantigen specific immune suppression, tolerance in infectious diseases, tolerance during pregnancy, and tolerance during various autoimmune diseases.