Sleep is universal. Every animal with a nervous system does it. Dolphins sleep with one hemisphere at a time. Migrating birds sleep in ten-second bursts mid-flight. Humans spend roughly a third of their lives asleep — twenty-five years for a person who lives to seventy-five. Sleep deprivation kills rats in two to three weeks (Rechtschaffen, 1989) and degrades human cognitive function within hours. Allan Rechtschaffen observed: "If sleep does not serve an absolutely vital function, then it is the biggest mistake the evolutionary process has ever made." And yet, despite a century of research, we do not know what that function is — or rather, we have too many answers and no way to unify them. The synaptic homeostasis hypothesis, proposed by Giulio Tononi and Chiara Cirelli (2003), holds that sleep restores synaptic weights that waking experience inflates. The memory consolidation theory, supported by decades of research from Robert Stickgold and others, argues that sleep replays and stabilises the day's learning. The glymphatic hypothesis, introduced by Maiken Nedergaard's group (2012), proposes that the sleeping brain flushes metabolic waste through a system of channels that open only during sleep. Immune function, emotional regulation, metabolic maintenance — all have been proposed as sleep's primary purpose. The Academy hosts Sleep in the Body School because the body's need for it is absolute and non-negotiable: no game can be played, no skill refined, no movement mastered without the nightly surrender whose purpose remains unclear.