Recently with the success of Java and the existence of different interfaces between VRML and Java, it became possible to implement three-dimensional Internet applications on standard VRML browsers (PlugIns) using Java. With the widespread use of VRML browsers, e.g., as part of the Netscape and Internet Explorer standard distributions, everyone connected to the Internet can directly enter a virtual world without installing a new kind of software. The VRML technology offers the basis for new forms of customer service such as interactive three-dimensional product configuration, spare part ordering, or customer training. Also, this technology can be used for CSCW in intranets. The reader should be familiar with programming languages and computers and, in particular, should know Java or at least an object-oriented programming language. The book not only provides and explains source code, which can be used as a starting point for own implementations, but it also describes the fundamental problems and how currently known solutions work. It discusses a variety of different techniques and trade offs. Many illustrations help the reader to understand and memorize the underlying principles.