The M.E. Society of America is an organization that seeks to promote understanding of the disease known as myalgic encephalomyelitis (ME/CFS), a multi-system disease adversely affecting the cellular mitochondria and the heart, brain, neuroendocrine, immune, and circulatory systems. M.E. was first described in the 1950’s following the recognition of many cases around the world, including a number of cases at the Royal Free Hospital in England. Many different viruses, bacteria, or toxins in combination with genetic factors may be involved in the etiology of the disease, which usually begins in childhood or early adulthood with an acute infection.