Whenever data are categorical and their frequencies can be arrayed in multidimensional tables, log-linear analysis is appropriate. Like analysis of variance and multiple regression for quantitative data, log-linear analysis lets users ask which main effects and interactions affect an outcome of interest. Until recently, however, log-linear analysis seemed difficult -- accessible only to the statistically motivated and savvy. Designed for students and researchers who want to know more about this extension of the two-dimensional chi-square, this book introduces basic ideas in clear and straightforward prose and applies them to a core of example studies. ILOG -- a software program that runs on IBM compatible personal computers -- is included with this volume. This interactive program lets readers work through and explore examples provided throughout the book. Because ILOG is capable of serious log-linear analyses, readers gain not only understanding, but the means to put that understanding into practice as well.