A survey of 11 introductory geology textbooks published over the last five years indicated that the classification of the igneous rock system introduced to high school seniors and freshmen/sophomore students at institutes of higher learning commonly is based only on the tripartite division of texture, composition, and color. In some of the surveyed textbooks, authors provide only the names and descriptions of a few select samples, never discussing or mentioning directly a classification scheme. Perhaps the most surprising aspect of the survey is that most working geologists would not use the simplified classification scheme promulgated by the authors. Instead, most would use a ternary classification for intrusive igneous rocks and lavas, while many volcanologists favor a textural-grain size scheme for pyroclastic rocks. Unfortunately, although ternary and textural-grain size schemes are highly regarded at the international level neither are mentioned in any of the introductory textbooks that were surveyed. It is not clear as to why the existing approach in introductory geology textbooks is favored over that used by the working geological community, although the following springs to mind. 1) The backgrounds of students enrolling in introductory classes are often highly varied, with some students having strong reasoning skills while the development of such skills in others is significantly weaker. 2) The majority of students enrolling in introductory geology classes are non-science majors who have little interest in the subject matter and are simply trying to fulfill the physical science requirement for their degree. 3) The ternary and texture-grain size classifications are commonly viewed as too formidable for an introductory class. For students and teachers to overcome the above three factors, they must have these tools that will allow students to enhance both their reasoning skills and their understanding of how to use a comprehensive classification. Moreover, this tool must be efficient and be readily available to them. Hence, a project was undertaken to develop a web-based tutorial with interactive Flash MX modules that will focus on mitigating the above enumerated problems through its ease of use and interactivity. This thesis consists of two parts. Part 1 is an interactive web-based tutorial on how to classify the igneous rock series. The audience for the web-based tutorial is high school seniors, and freshmen and sophomore college students in an introductory geology class. Part 2 consists of four chapters. Chapter II introduces the reader to the user interface in Flash MX, while chapters ill, IV, and V represent detailed discussions on how different aspects of the web-based tutorial were developed in Flash MX. For example, Chapter ID takes the reader through the logic and steps necessary to fully develop in ActionScript, the scripting language used in Flash MX, an interactive ternary classification diagram. A similar approach is used in Chapter IV for the development of an interactive bivariate graph. Chapter V outlines the ActionScript methods for developing a point-count machine within the Flash MX framework.