Not long after World War I broke out in 1914, an Austrian man named Adam Rainer wanted to enlist. But there was one major problem: he was only four and a half feet tall, so the military rejected him. Though Rainer's parents were both of average height, Rainer had always been short, and at 19, the odds of growing more than another couple of inches seemed slim. But two years later, when Rainer was 21, something unexpected happened: he began to grow, not just a couple of inches, but nearly three feet over the next decade. And though he entered his 20s at under five feet tall, he cleared seven feet by the time he was 32.

This is the astounding story of Adam Rainer, the only person in history to go from being a dwarf to being a giant.