Abstract: Apparatuses and methods to enhance sleep, reduce sleep onset latency, extend sleep duration and/or increasing the duration of deeper sleep stages relative to stage 1 sleep. In general, these apparatuses and methods apply and maintain one or more target “warm” temperatures to a subject's forehead for a time period. The target temperature may be between 25° C. and 42° C. The target temperature may be a fixed amount greater than ambient temperature. The time period may be a fixed time period or a variable time period. These methods and apparatuses may limit the application of thermal energy to the subject's forehead region.