Revision with unchanged content. Recently the number of applications in the Internet which use data broadcasts, such as pay-per-view services, has increased greatly. In broadcast scheduling one is interested in answering user requests in such services with as little bandwidth as possible by bundling the answers appropriately. Flows over time are an important notion arising in connection with various applications in communication and transportation networks. One of the basic question here is how can demands in a given network be routed to their destinations as quickly as possible? Economic relationships in the Internet are of great interest, e.g., when investigating robustness issues. Since they are treated as trade secrets, it is a challenge to infer them form samples of routes taken by packets in the Internet. The author Alexander Hall gives introductions and several novel results for these three problem areas. Some of the main results resolve the complexity of the major optimization problems encountered in the three areas. Thereby, important and in some cases long-standing open questions have been answered. From an algorithmic point of view, optimal and approximation algorithms for each of the three areas are proposed. This book is of interest to scientists in academia and industry working on research problems pertaining to communication and transportation networks.