Networked computer games, distributed virtual reality systems and shared whiteboard presentations are prominent examples of "distributed interactive media" - they allow a group of users to interact with the medium itself. This book investigates the distributed interactive media class in detail. Topics include: abstract media model, how to ensure consistency, an application-level protocol and how to develop reusable functionality such as support for late-comers and session-recording. The main intention of this book is to demonstrate that distinct distributed interactive media have many problems in common and to show how to solve these problems in a generic and reusable fashion for the whole media.