A Bozeman resident and former Wallace Stegner Professor in Western American Studies at MSU, Quammen published “Ebola: The Natural and Human History of a Deadly Virus” last fall in response to public and media bewilderment about the disease, after circumstances became more severe in West Africa. Quammen drew on material from his compendious 2012 book, “Spillover: Animal Infections and the Next Human Pandemic” to assemble this new little volume, adding a fresh introduction and an epilogue devoted to recent events.