The worlds synthesized in the cyberspaces of networked computers are the theme of Cyberworlds. Cyberspaces have come into prominence with the de­ velopment of the Internet and are expected to expand drastically with the emergence of national and international information systems. The purpose is to discover the architecture and design of cy­ of the book Cyberworlds berworlds by synthesizing worlds in cyberspaces. The underlying philosophy is crucial to the success of the architecture, and an initial effort is made to delineate it at the beginning of the book. The book's topics are selected to clarify the issues of the philosophy, architecture, and design of cyberworlds through a wide variety of case studies. The approach presented in the book is thus characterized as synthetic rather than analytic. There already are numbers of books with observations and analyses of cyberworlds. They warn of the danger of widespread crimes and accidents in the cyberworlds, for instance. Without a philosophy and methodologies of how to architecturally design and synthesize the cyber­ worlds, the worlds in cyberspaces tend to be arbitrarily extended, disordered, and, in extreme cases, criminal. This book is intended to benefit readers by providing them with a possible direction to take in deciding how to synthesize worlds in cyberspaces. Cre­ ating new worlds in new spaces with almost unlimited dimension and scale is an immense challenge. In principle, anyone at any moment can participate in the creation. The book serves as a creator's reference and also as a design guidebook.