Tim Cook took over as Apple’s CEO on August 24, 2011—just six weeks before Steve Jobs died. In the fifteen years since, Apple’s revenue jumped 303%, profit rose 354%, and its market value exploded from $297 billion to $4 trillion. Cook inherited Jobs’s breakthrough work: the Mac, iPod, iPhone and iPad. His strength lay not in inventing new product categories from scratch, but in scaling them worldwide and squeezing out cost, complexity and risk. Long before the iPhone became a global phenomenon, Cook overhauled Apple’s operations. He closed Apple’s own factories and warehouses, moved manufacturing to China on a just-in-time model, and built a supply chain that reliably delivers hundreds of millions of devices each year. No significant recalls marred his record. He also launched stores in dozens more countries and introduced peripherals like AirPods and Apple Watch—together pulling in $35.4 billion last year, a Fortune 500–sized business. Cook pushed Services as a profit engine. The Google deal—dating back to 2002—made Google the default search provider on Safari and still brings Apple pure profit. The App Store, launched under Jobs, turned into a revenue stream cooking off billions in annual profit. In mid-2011, Phil Schiller suggested cutting Apple’s 30% fee to win more developers; Cook stuck with the status quo, cementing Apple’s role as gatekeeper and cash machine rather than ceding margin for broader ecosystem growth. What makes Apple tick today traces to values Cook codified in Apple University: focus on a few great products, own key technologies, keep designs simple, say no to distractions, collaborate tightly across teams, and demand excellence. Those principles didn’t create the iPhone, but they turned it into a multi-trillion-dollar franchise—and set up Apple’s next generation of bets, from augmented reality to services.