Multiple sclerosis (MS) is referred as the most prevalent demyelinating disease, where the insulating covers of nerve cells in the spinal cord and brain are destroyed. This injury impairs the capability of the parts of nervous system to transmit signals. This leads to a variety of signs and symptoms such as mental, physical and occasionally psychiatric issues. Problems with coordination or sensation, double vision, muscle weakness and blindness in one eye are some of the major symptoms. The etiology of MS is unknown; but numerous risk factors have been linked to its pathogenesis, comprising a link between environmental agents and genetic vulnerability. The breakdown of myelin sheaths of neurons, creation of lesions in the central nervous system and inflammation are the three basic characteristics of MS. This book is compiled in such a manner, that it will provide in-depth knowledge about the etiology and pathophysiology of multiple sclerosis. It aims to shed light on some of the unexplored aspects of this disease. Researchers and students in this field will be assisted by this book.