Advances in biochemistry, cell biology, genome-wide mutagenesis - coupled with molecular technology, including gene microarray and transgenic and knock-out animals - have been instrumental in understanding the cellular processes and molecular pathways of self-tolerance and autoimmune diseases. The molecular definition of these pathways and processes has led to novel treatments for certain auto-immune diseases that are based on the pathogenesis of diseases rather than on broad-spectrum immunosuppression. This book reviews many of these current developments and proposes future novel approaches for understanding the pathogenesis of auto-immune diseases and designing novel therapy. This book covers three major areas of auto-immunity: the basic mechanisms of immunological tolerance, pathogenesis of auto-immune diseases, and some novel therapies. This book should be useful for immunologists, molecular biologists, rheumatologists, and clinical scientists.