Introducing a book on global infectious diseases is a daunting challenge. Modern developments in molecular research, newly available opportuni- ties for earth-orbiting, satellite-based surveillance as a means of predicting certain regional epidemics, and the introduction of remarkable new anti- biotics which can cure some awesome problems such as river-blindness would each have astonished even the most jaded reader only a few decades ago. Just the same, even with these laudable advances, malaria is still with us and both poliomyelitis and tuberculosis are growing worldwide problems. As a holdover from my own medical school days, I must confess to an affection for the older term of "tropical medicine" and its historic context, in preference to the more popular present name which is the title of this book. A century or two ago the motives to study tropical medicine were obvious: nations having enormous amounts of maritime trade with distant lands established colonial empires where health in the colonies was a con- cern for both the natives and the colonists. It is unsurprising that the great institutes for such studies sprang up in London, Amsterdam, Hamburg, New York and New Orleans, but few of these centers and other similar ones have continued to flourish or even to survive, perhaps because the days of empires have gone.