The non-entrained life of a young gentleman at Oxford.

Sleep logs over 9 months document the delayed sleep phase of a healthy male student at Oxford. The lack of any imperative zeitgebers also permits the rest-activity cycle to exhibit very long (circabidian) days similar to those seen under conditions of temporal isolation. No psychopathology or subjective distress was associated with this unusual rest-activity cycle: It was a preferred life-style.