Almost 50 million persons visit another continent each year. It is mainly those 15-18 million travelers from industrialized nations who visit or reside in developing countries that are at increased health risk. To develop effective health protection advice, the health risks of travel and the benefits of prophylaxis (vaccines, new and old drugs, behaviour modification, etc.) should be assessed systematically. The purpose of this book is to improve the protection of the travelers' health by more effective and more uniform recommendations. It contains many data on recent research and represents the first comprehensive account on travel medicine for professionals.