This is a work of reportage that relies on hundreds of interviews with sources, including many who spoke with me on the condition that their names be withheld. Some of the sources sought anonymity to speak freely without fear of repercussions; others would have declined to be interviewed at all. Where possible, I have added attributions in the text and tried to be specific about the nature of the anonymous source, so that the reader may better assess the information presented. If specific attribution is not provided, the reader should assume that the information is synthesized from multiple accounts of an event or experience. Bill Gates, his representatives at Gates Ventures, and representatives of the Gates Foundation did not participate. Once presented with the information in this book, they stonewalled for months. Following multiple entreaties, both organizations initially said they would not comment on “hearsay.” Just days before the book went to print, a representative of Gates Ventures offered some comments, which are reflected in the text.