For some, sleep is labelled as a daily commodity, slotted in somewhere during the day. For others, it is a luxury. We all have created a relationship with the non-waking state where we allow drifting away from the daily chores of life and move into a world of rest and recuperation. Our sleep cycles are intertwined with our biological clock, our internal mechanism regulating the 24 hours cycles. So-called circadian rhythms, it is these consistent patterns of rising and falling of hormones indicating that sleep is soon upon us or whether we are permitting light to enter our eyes. For...