You spend hours drilling flashcards, rewatching lectures at double speed, and telling yourself that one more all-nighter will finally make the material stick. Then the exam arrives and your brain goes blank. Here is the frustrating truth: most study time is wasted not because you study too little, but because you sleep too little. Learning does not finish when you close the textbook. It finishes while you sleep. The science of memory consolidation shows that sleep is not a pause in learning. It is the engine that turns fragile new knowledge into durable, usable skill.