Recently, with the success of Java and the existence of different interfaces be­ tween 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 Com­ municator and Microsoft's Internet Explorerstandard distributions, everyone connected to the internet via a PC ( and some other platforms) can directly enter a virtual world without installing a new kind of software. The VRML technology offers the basis for new forms of customer services, e.g., interactive three-dimensional product configuration, spare part ordering, or customer training. Also this technology can be used for CSCW in intranets. This book has a theoretical and a practical part. The theoretical part is intended more for teachers and researchers, while the practical part is in­ tended for web designers, programmers and students, who want to have both a hands-on approach to implementing Web 3D applications and a technically detailed overview of existing solutions for specific problems in this area.