In a searing investigation into the once lauded biotech start-up Theranos, Nick Bilton discovers that its precocious founder defied medical experts—even her own chief scientist—about the veracity of its now discredited blood-testing technology. She built a corporation based on secrecy in the hope that she could still pull it off. Then, it all fell apart. ... At Theranos, Holmes preferred that the temperature be maintained in the mid-60s, which facilitated her preferred daily uniform of a black turtleneck with a puffy black vest—a homogeneity that she had borrowed from her idol, the late Steve Jobs. ... Holmes had learned a lot from Jobs. Like Apple, Theranos was secretive, even internally. Just as Jobs had famously insisted at 1 Infinite Loop, 10 minutes away, that departments were generally siloed, Holmes largely forbade her employees from communicating with one another about what they were working on—a culture that resulted in a rare form of executive omniscience. At Theranos, Holmes was founder, C.E.O., and chairwoman. There wasn’t a decision—from the number of American flags framed in the company’s hallway (they are ubiquitous) to the compensation of each new hire—that didn’t cross her desk. ... And like Jobs, crucially, Holmes also paid indefatigable attention to her company’s story, its “narrative.” ... In a technology sector populated by innumerable food-delivery apps, her quixotic ambition was applauded. ... she is often surrounded by her security detail, which sometimes numbers as many as four men, who (for safety reasons) refer to the young C.E.O. as “Eagle 1”—and headed to the airport. (She has been known to fly alone on a $6.5 million Gulfstream G150.) ... it is impossible to get a precise result from the tip of a finger for most of the tests that Theranos would claim to conduct accurately. When a finger is pricked, the probe breaks up cells, allowing debris, among other things, to escape into the interstitial fluid. While it is feasible to test for pathogens this way, a pinprick is too unreliable for obtaining more nuanced readings. Furthermore, there isn’t that much reliable data that you can reap from such a small amount of blood.