Do you have a hard time getting to sleep? Do you sometimes wake up in the night? After reading about the patients of clinical neurologist Dr. Guy Leschziner, you might realize that you have it pretty good. Leschziner is a world authority on sleep conditions such as narcolepsy, restless leg syndrome, and night terrors. He also treats patients with far rarer conditions, like sexsomnia (no, really, it’s a thing) and Kleine-Levin syndrome, where patients become profoundly sleepy and scarily hungry.

In Leschziner’s lively new book, The Nocturnal Brain, we meet Vincent, a patient whose circadian clock shifts an hour forward each day, leaving him out of sync with the rest of society. Then there’s sleep-driver Jackie, who takes jaunts on her motorcycle while seemingly unconscious. And sleep-eater Don once consumed an entire bowl of birdseed slathered in salad dressing. The range of disorders associated with sleep, Leschziner reveals, is staggering.

Mysteries about sleep persist. No one fully understands, for example, why some people experience sleep paralysis—the sensation that they are awake but cannot move because something is pressing on them. The connection between sleep and diseases such as Parkinson’s and Alzheimer’s remains to be fully unraveled.

Whether you personally suffer from a sleep disorder, love someone who does, or simply enjoy learning more about the human brain, this fascinating book will definitely not put you to sleep.