In his performances--which often extend over several weeks or months--the Icelandic artist Ragnar Kjartansson (born 1976) explores not only his own physical and psychological limits and the themes of early performance art, but also the artist's status and the different images of his role. For his installation "The Schumann Machine" (2008), created for Manifesta 7, he spent several hours every day for two weeks singing the 1840 song cycle Dichterliebe...