It has long been known that daylight is a critical signal in keeping the “biological clock” (circadian rhythms) on time, consequently regulating the sleep wake cycle in humans and lower animals. Two relatively common sleep disorders, sleep phase delay, and sleep phase advance, have been recognized in humans. These disorders may respond to bright light therapy. Sleep phase delay (inability to initiate sleep, and to awaken at relatively normal times) is most frequently observed in adolescents and young adults, and may be treatable with two-to-three hours of bright light therapy applied in the morning for several days. Sleep phase advance (falling asleep, and wakening too early) is common in the 65-years plus age group, and can be treated with bright light applied in the evenings. These disorders can be complicated to treat, and we recommend that people with these problems consult a sleep-medicine specialist. A summary of relevant published data was published in Sleep, Vol. 22, No. 5, 1999. Jet lag is classified as a sleep disorder, which simply stated is the inability of the biological clock of the jet-airplane-traveler to normally reset rapidly to a new time zone. BioBrite has devised a program involving the Light Visor that manipulates light to rapidly reset the biological clock. The program is soundly based scientifically, and its efficacy is supported by a number of antidotal reports by users. BioBrite received a Small Business Research grant from the National Institutes of Health to support a controlled field trial of the program in normal human volunteers. Melatonin has been reported to be helpful in preventing jet lag. However, a large controlled field trial failed to demonstrate efficacy (Spitzer, R.L., et. al.; American J Psychiatry 1999; 156). Furthermore, melatonin is still considered by scientists to be an experimental drug, and “over-the-counter” preparations are not regulated by the FDA.