Sleep restriction therapy (SRT) is indicated for the treatment of insomnia, including trouble sleeping during the beginning, middle, or end of the time spent in bed. SRT is indicated for sleep difficulties in which the subjective sleep efficiency, based on a 1- to 2-week sleep log or retrospective report, is less than 85 percent. There is no systematic evidence that SRT is the treatment of choice for a particular insomnia. The increased sleep propensity produced by SRT (especially at the start of treatment) will make patients sleepy. Therefore, individuals who need to maintain optimal vigilance to avoid serious accidents should not engage in SRT. Individuals who fall asleep quickly and have short, compact sleep prior to a terminal early morning awakening are unlikely to benefit from SRT. In these cases restricting time in bed will not reduce sleep latency, not reduce the number or duration of awakenings, and not likely increase the duration of sleep. Judgment will be necessary when patients report that they stay in bed “completely awake” just to rest. The ability to perceive sleep is imperfect and individuals may be unaware that they are getting some sleep after the major sleep period. In cases, where some light or unappreciated sleep does occur at the end of the night, SRT may be beneficial.