Steven's list includes titles such as Plagues and Peoples and The Hot Zone, which I've heard of but never read. My own preferences for discussions of catastrophic plague outbreaks lean more towards broad cultural analysis, so I have to mention two titles. Guns, Germs, Steel is one of the best books I've ever read, and beyond its discussion of the importance of germs, it gives readers an entirely different framework for thinking about the evolution and competition of cultures. Another title which I haven't finished yet but am thoroughly enjoying is 1491, which offers a unique perspective on pre-Columbian America. (Author Charles C. Mann has also actively participated in the book's Amazon forum as well, which is great to see.)
The HIV pandemic and the threat of malaria or SARS or ebola or avian flu all show that germs can still be a significant danger today. But what's interesting to me is that there's been such a dramatic change; For those of us in the developed world, something like smallpox isn't an everyday concern, let alone a mortal danger. So the looming threat of genocide due to a viral danger is mostly something we can read about as voyeurs without actually being terrified.
My interest in these books isn't purely morbid, though. Hundreds or thousands of years ago, the greatest danger that faced societies was the introduction of a foreign culture's physical threats. I think these books are deeply instructive in a modern context, though, because the greatest threat to cultures today comes from not intermingling. Whether it's expressed in agriculture ("hybrid vigor"), or in the context of a cocktail party (being a "social butterfly"), making an effort to avoid cultural isolation is rewarded by making an individual or a society more healthy. That's not to mention the bonus potential of additional opportunities, higher potential for recognition, a larger market for trade or commercial interests, and a broader audience for communication of messages.
For most of history, peopled feared outsiders because they really could pose a mortal threat to an existing culture. Now that the situation has reversed, we have to have put just as much energy into reaching out from within our monoculture, not just because of our desire to be inclusive, but also for the health of our own culture. I see examples of this every day, especially from parents, as they choose not to let their children use antibacterial soap or start to explore the increase in asthma or allergies among children. In each of these cases, getting exposed to the germs we used to strive to avoid is necessary to keep healthy.
So, are there any great plagueographies that I'm missing? This honestly isn't a topic that I know very well, and I'd love to learn more about what research is being done.