Introduction

If you are often involved with multivariate data analysis, you will be familiar with terminologies like Principle Component Analysis, Factor Analysis, Clustering...and so on. However most of these techniques are trying to plot a multidimensional data set onto a 2 or 3 dimensional space, and hence we may lose information that are hidden in other dimensions. If you have been using a UNIX-based system, you may be familiar, or may have heard of the free program called XGobi^7.1, http://www.research.att.com/areas/stat/xgobi/index.html#xgobi. Unfortunately setting up XGobi with Windows environment is a non-trivial experience, and involves you have a proper X-Server running on top of your Windows. Recently there has been a new development called GGobi, http://www.ggobi.org/. At the time I write this chapter, GGobi is stable enough for a normal user.