The young Tesla engineer was excited. Ecstatic, in fact. It was a Saturday in October 2017, and he was working at the Gigafactory, Tesla’s enormous battery manufacturing plant in Nevada. Over the previous year, he had been living out of a suitcase, putting in 13-hour days, seven days a week. This was his first real job. And now a colleague had tracked him down to say that Elon Musk—Elon Musk!—needed his personal help. The previous year, Musk had made an audacious announcement: His company, which was known—fetishized, actually—for its luxurious electric vehicles, would soon begin manufacturing a new sedan that it planned to sell for just $35,000, putting it within reach of the middle class. The Model 3, Tesla hoped, would transform the auto industry by proving that a mass-produced, emissions-free vehicle was not only feasible but profitable. If successful, the vehicle would help end humanity’s addiction to fossil fuels, slow climate change, and show that ingenuity and ambition could accomplish nearly anything. Within a year of that announcement, however, work on the car was behind schedule. There were problems in battery manufacturing, parts construction, development of assembly lines. Tesla’s goal was to build 5,000 vehicles a week; recently the…