The emergence of strange new diseases—Ebola, SARS, Hendra—is a frightening problem that seems to be getting worse: In this age of speedy travel, it augurs a worldwide pandemic. Even scarier, says science writer David Quammen: Such phenomena are part of a single pattern, as the bugs that transmit these diseases all originate in wild animals and pass to humans by a process called spillover. His book, appropriately titled Spillover, tracks this subject around the world to learn how, where from, and why these diseases emerge, and then asks: What might the next big one be? Presented as part of Town Hall Science series, sponsored by University Book Store and Microsoft. For more information on how to register, click here.