Can one obtain new insights by comparing the motion of bacteria or plancton striving for food and light with that of pedestrians in a crowded street? Do complex transport networks behave similarly under high load, be it the internet or downtown city traffic? These and related questions were topics of the international workshop on Traffic and Granular Flow '97, which took place in Duisburg, 6-8 October, 1997 (as part of the 25th anniversary of the Gerhard-Mercator-Universitat, Duisburg). The contributions contained in the book reflect the enormous research activities in this interdisciplinary field which attracts increasing public attention.