Ngoc Thai is an extreme insomniac. He claims that he hasn't slept for the better part of 38 years. He says that, after a battle with fever in 1973, he lost the ability to sleep.
This isn’t necessarily a good thing for him. In recent interviews, he's said that he is starting to feel grumpy from lack of sleep. He's tried many things, including medication and alcohol, and nothing seems to work.
Doctors have examined him and found him to be otherwise healthy. The man is a farmer and is still able to do all the farm work. In fact, he does extra farm work since he has all that extra time.
What doctors haven't really examined yet though, is if he actually doesn't sleep. While there are many news reports about him, no one has really dug into his claims. Some doctors think that many insomniacs lose perception of sleep vs. awake, so when they think they might be just resting, they're actually taking micro-naps.