Autoimmune diseases (ADs) occur when the immune system is mistakenly activated and attacks self antigens present in our body, leading to tissue destruction. Increasing prevalence of ADs is not only a problem for the affected patients but also causes enormous economic burden to the society. Genetic, environmental and epigenetic factors, and interactions between them contribute to the clinical disease outcome. Although most of these diseases are polygenic and multifactorial, and the clinical spectrum differs significantly between the ADs, shared genes and pathogenic pathways attacking specific tissues or organs do exist. Hence, better understanding of the immunological and pathological basis of these diseases will help to design early diagnostic methods, identify new drug targets, optimize treatments to alleviate sufferings of patients, and develop vaccines and methods to control progression of disease manifestations. This book is organized into seven chapters: Detailed description of Multiple Sclerosis (MS), Inflammatory Bowel Disease (IBD) and Psoriasis (Ps); Antibody mediated disease pathogenesis in Rheumatoid arthritis (RA) and type I diabetes (T1D), antibody glycosylation and its critical role in its effector functions; macrophages in inflammation and its resolution and, the use of nanoparticle-based drug delivery systems for ADs are discussed in detail.