navtu pEt - everything flows Heraclit, 540-480 AC Everything flows - everything changes. I Heraclit's aphorism summarizes this book and its content in several ways. Flow refers to things passing by, it alludes to the intangible and immaterial, which is the essence of information technol ogy. But flow also refers to move, which is the core oftourism. Both, the tourist and the information are traveling: the tourist is traveling to the destination, the information about the tourism product is traveling to the consumer. Finally, the aphorism refers to permanent change. Industries, the IT as well as the travel and tourism industry, are constantly changing our way of life, our views and per ceptions of life. Moreover, these industries themselves undergo a permanent change. There are other parallels: both industries are not only growing above average, they will also be among the most important industries in the next cen tury. In addition to these similarities, both industries are closely interrelated and intertwined. This interrelationship is not a recent phenomenon, even though it has not been explicitly observed before. It started in the early days of comput ing, and is becoming increasingly intense, up to the point, where IT is probably the strongest driving force for changes within the tourism industry. At the step to the next millennium, mankind is witnessing rapidly evolving technological progress, together with huge changes in human society.