This lecture will introduce concepts, etiology, pathophysiology, and the diagnosing and treatment of multiple sclerosis (MS).  The presentation reviews important components of neuroimaging related to multiple sclerosis, as well as discusses the subtypes, and natural history of relapsing multiple sclerosis.  The presenter discusses the demographics more highly affected by multiple sclerosis, the symptoms experienced over time, as well as red flags and mimics, and relapse and reactivation.  Finally, the presentation will discuss therapies and effectiveness over time, and review risk factors and complications.