Why We Sleep

Matthew Walker's 2017 bestseller (Scribner) arguing that sleep is the foundation of health and cognition. Walker, a neuroscientist then directing UC Berkeley's Center for Human Sleep Science, surveys two decades of research on memory, immunity, emotional regulation, and disease, and prescribes seven to eight hours a night as a biological necessity rather than a lifestyle choice.

Gates's review is unusually personal. "Now that I've read Matthew Walker's Why We Sleep, I realize that my all-nighters, combined with almost never getting eight hours of sleep, took a big toll." He ran early Microsoft on caffeine and adrenaline, twice stayed up two nights straight, and thought sleeping a lot was lazy. The founder angle is recovery as a performance input: the book's case that sleep underwrites decision-making, creativity, learning, and emotional control — the exact inputs a founder burns fastest.

But read it with a discount, and the book's own readers built the discount. Gates flagged it first: Walker "sometimes reports as fact what science has not yet clearly demonstrated," particularly the strong Alzheimer's link. Then in 2019 Alexey Guzey's fact-check, 'Matthew Walker's Why We Sleep Is Riddled with Scientific and Factual Errors,' documented misrepresented studies and overstated claims, and Walker's responses satisfied few critics. The durable core — consistency, a cool dark room, alcohol as a REM suppressant rather than an aid, the near-zero population who thrive on five hours — survives the audit. Treat the scarier mortality statistics as contested, and the operating advice as sound.