The French physician Maurice Raynaud was the first to describe a paroxysmal circulatory disorder of the fingers induced by cold in 1862, thus giving the phenomenon its name. The majority of cases appear on the grounds of a functional disorder of digital arteries. On the other hand, Raynaud's phenomenon can also indicate an underlying disease, such as systemic sclerosis or lupus erythematosus. The symptoms vary from mild to severe and can be accompanied by frequent painful attacks and tissue necrosis. This not only results in a reduction in quality of life, but can possibly even lead to lifelong unemployment. In any case, a multidisciplinary approach is essential. This textbook summarizes recent facts on all aspects of peripheral ischemic syndromes from differential diagnoses to the latest developments in therapy.