I’m yawning, writing this article. (Has anyone put together a montage of yawns to show to insomniacs?) Most of these books about sleep (and many more) are available to borrow for free from the Internet Archive. *As an Amazon Associate, I earn from qualifying purchases.
The Secret Life of Sleep, by Kat Duff
Secrets of Sleep, by Alexander Borbély
Sleep and Dreams, by Andrew T. McPhee
Why We Sleep: The Functions of Sleep in Humans and Other Mammals, by James Horne
Why We Sleep: Unlocking the Power of Sleep and Dreams, by Matthew Walker
This highly rated book, from 2017, looks at the same question as the above book: “Why do we sleep?” — but 19 years later and from a very different perspective. It is to buy, not available in the Internet Archive. Buy*
Sleep Thieves: An Eye-Opening Exploration Into the Science and Mysteries of Sleep, by Stanley Coren
*As an Amazon Associate, I earn from qualifying purchases.