Summarize Preston's experience with Africa.

I don't know what extent Preston's direct experiences are with Africa were. Preston undertook extensive investigation and research in order to expand his original article into a full-length book. He explains his process of research on his personal website, writing: “When I’m researching a book, I immerse myself in the lives of my subjects. I try to experience their worlds from within. I take extensive notes in small notebooks that I carry in my pocket. I use a digital camera, too. I am a compulsive fact-checker, calling people on the telephone, re-interviewing them, checking what I’ve written, doing my best to confirm verifiable details. (I once spent hours with Colonel Nancy Jaax at her kitchen table, inspecting her hands carefully so that I could describe her hands. At the same time, I was asking Colonel Jaax things like 'What was going through your mind at the moment you discovered you had Ebola blood running around inside your space suit?’)”