Arfath Saleem

For David Goggins, childhood was a nightmare--poverty, prejudice, and physical abuse colored his days and haunted his nights. But through self-discipline, mental toughness, and hard work, Goggins transformed himself from a depressed, overweight young man with no future into a US Armed Forces icon and one of the world's top endurance athletes. The only man in history to complete elite training as a Navy SEAL, Army Ranger, and Air Force tactical air controller, he went on to set records in numerous endurance events.

In 1999, legendary venture capitalist John Doerr invested nearly $12 million in a startup that had amazing technology, entrepreneurial energy and sky-high ambitions, but no real business plan. Doerr introduced the founders to OKRs and with them at the foundation of their management, the startup grew from 40 employees to more than 70,000 with a market cap exceeding $600 billion. The startup was Google.