Distributed service networks encompass various facilities with which we have daily contact. In the public sector they include, for instance, ambulance, fire, and police services; in the business sector they include maintenance and repair services, road services, courier services, and the like. Policy making problems in distributed service networks can be clearly classified into a number of hierarchical levels. The levels are distinguished by the time horizon of the problem, by the amount of cost involved in the implementation of a solution, and by the political implications of the solution. This top-down classification is typical of what is known as the "e;systems approach,"e; advocating that the direction of the analysis of complex systems should be from the whole to the details. The top-down classification consists of the following categories of policies: 1. Zoning: How should a network be partitioned into subzones? 2. Station location: Where should service stations or service units be located? 3. Resource allocation: What amount of resources should be allocated to the stations? vii viii Preface 4. Dispatching, routing, and repositioning: What is the optimal dis- patching policy, what are the optimal routes for nonbusy units, and under what circumstances is it worthwhile to reposition a certain idle unit? A top-down approach implies that each of the problems is solved separately; however, the solution of a higher-level problem sets constraints on problems at lower levels.