Restless legs syndrome (RLS) is a disorder that was first described by Thomas Willis in 1672. Much later, authors referred to this condition variably as “anxietas tibiarum” and “leg jitters.” On the basis of a large series of patients, Ekbom, a Swedish physician, coined the term “restless legs” in 1944 and gave the first full clinical description of RLS. Thus, RLS is sometimes referred to as “Ekbom’s syndrome.” He found that about 5% of normal subjects report occasional crawling sensations in their legs and that familial clustering occurs in some cases. He also described secondary forms due to anemia or pregnancy. Ekbom’s son later described instances of RLS after gastric surgery, presumably due to iron deficiency.