Over the past two decades, no company has had such a profound impact on the American workforce as Amazon. As the country’s second-largest employer, the e-commerce giant has hired hundreds of thousands of warehouse workers, built an army of contract drivers and pushed forward the use of technology to hire, monitor and manage its workforce. But now, according to internal strategy documents and interviews, Amazon is facing its next huge turnaround. Over half a million employees are to be replaced by robots.