Autoimmune disorders are known to affect a substantial number of people worldwide, demonstrating a gender bias and are the second largest cause of chronic illness. Recently, the attention has been focused on lifestyle changes as a major factor in the rise of autoimmune disease frequency. The two sections of this book are focused on the new opportunities for moving research forward, leading to a new approach to prevention and treatment of autoimmune diseases. A better understanding of the mechanisms of gene expression and triggering signaling pathways, which is involved in autoimmune pathogenesis simultaneously with current data for the interaction of microbiota with human immune system, will help to better understand the immune imbalance implicated in autoimmunity.