Travis Kalanick is best known for co-founding Uber and building it into one of the world’s largest transportation platforms. Before Uber, he spent years building Red Swoosh under extreme financial pressure. He says he took no salary for its first four years, repeatedly ran out of money and lost much of his social life to the company before eventually selling it. He later invested much of the proceeds in friends’ startups, becoming the first investor in Expensify.

Kalanick started Uber at 33 and carried the intensity of those earlier years into the company. He describes operating with “precision, perfection and obsession” and continued running Uber with the mentality of someone worried about making the next grocery bill even after the company had reached a valuation of roughly $70 billion. Under his leadership, Uber expanded rapidly across cities and countries, creating a new category of app-based transportation and challenging the entrenched taxi systems that controlled many local markets.