Computational science is a quickly emerging field at the intersection of the sciences, computer science, and mathematics because much scientific investigation now involves computing as well as theory and experiment. However, limited educational materials exist in this field. "Introduction to Computational Science" fills this void with a flexible, readable textbook that assumes only a background in high school algebra and enables instructors to follow tailored pathways through the material. It is the first textbook designed specifically for an introductory course in the computational science and engineering curriculum. The text embraces two major approaches to computational science problems: System dynamics models with their global views of major systems that change with time; and cellular automaton simulations with their local views of how individuals affect individuals. While the text is generic, an extensive author-generated Web-site contains tutorials and files in a variety of software packages to accompany the text. It features: generic software approach in the text; web site with tutorials and files in a variety of software packages; engaging examples, exercises, and projects that explore science; additional, substantial projects for students to develop individually or in teams; consistent application of the modeling process; quick review questions and answers; projects for students to develop individually or in teams; reference sections for most modules, as well as a glossary; and online instructor's manual with a test bank and solutions.