The Circadian Clock Laboratory researches the detailed biomolecular mechanisms of the circadian clock, the bodily and behavioral changes tied to the 24-hour daily cycle that synchronize to daylight and darkness. Increasingly, these patterns are disrupted by modern urban culture, including the omnipresence of artificial light and frequent travel across time zones. To explore the biochemical mechanisms that underlie these daily rhythms, we study the reconstituted in vitro circadian clock from a cyanobacteria, Synecochoccus elongates. The bacteria’s central oscillator is encoded by three genes, kaiA, kaiB, and kaiC, whose protein products function together to generate a 24-hour rhythm of KaiC phosphorylation. The 24-hour KaiC phosphorylation rhythm is generated by the timely association and dissociation of these three Kai proteins. The laboratory works with biophysicists and mathematical biologists to examine hypotheses about the circadian clock’s molecular mechanisms. By exploring them at this level, we expect to obtain critical clues for the treatment of medical problems related to the clock’s disruption, including sleep deprivation and jet lag.