Acute myelopathies are a diverse set of illnesses with different causes, clinical and radiologic characteristics, and prognoses. An immune-mediated mechanism produces neural damage to the spinal cord, leading in variable degrees of weakening, sensory changes, and autonomic dysfunction. Transverse myelitis (TM) is a prototype member of this category. TM can occur as part of a multifocal CNS disease (e.g. MS), a multisystemic disease (e.g. systemic lupus erythematosus), or as a standalone, idiopathic condition. Our knowledge of the classification, diagnosis, pathophysiology, and therapy of TM has just lately begun to grow. With more stringent criteria for distinguishing acute myelopathies and a better knowledge of the immunopathogenic processes that underpin TM, it may now be possible to start treating many of these illnesses effectively. We are learning more about the pathways that contribute to autoimmune neurologic disorders in general as a result of our research into TM.