A dorm room in 1984. Michael Dell started selling computers built to order and shipped direct, cutting out the retailer entirely, and the personal-computer industry never quite recovered its old shape. He became one of technology's youngest self-made billionaires on that model alone.
Then the PC market matured, which is a polite way of saying the growth stopped. His response was drastic: take the company private in one of the largest such deals ever done, and rebuild it away from quarterly scrutiny.
He took his own public company private to fix it away from the market's glare — then brought it back stronger.
The rebuild ran through EMC. Buying the data-storage giant turned Dell into a broad enterprise-technology group — servers, storage, software, services — and only then did the company return to public markets.
From disruptive upstart to elder statesman of enterprise computing is a long arc, and the interesting part is the middle. He was willing to make an enormous financial bet purely to control the company's own direction.