An accessible, science-led exploration of why we sleep, written by neuroscientist and sleep researcher Matthew Walker. It works through the big questions a curious reader actually has: what sleep is, what happens during the night, how much we really need, and why being a night owl or a morning lark is a real thing. Drawing on twenty years of research and studies from across the animal kingdom, it makes a complex subject genuinely readable. Worth exploring for anyone who wants to understand the science of sleep rather than just be told to get more of it.