Into Thin Air is a play on words that illustrates a few key facts about the 1996 Everest disaster. It’s a play off the phrase "disappear into thin air." That’s what happened up on Everest that fateful day: Over a dozen climbers abruptly went missing in the blink of an eye. But it’s also a reference to the fact that the book takes place at high altitudes, where the air is quite literally, thin. The oxygen deprivation caused by this "thin air" is hugely important to the events of Into Thin Air, though you’ll have to read the book yourself to find out why.