BOOK REVIEWS An R and S-PLUS Companion to Applied Regression. By John Fox.

Linear Models, and Related Methods, is an introduction to linear models that begins with least squares fits, covers a range of diagnos-tic methods, and ends with chapters on logistic regression and various extensions to the linear model, including generalized least squares, robust estimation, and nonparametric approaches. The book is thor-ough in its treatment of the underlying theory but also strongly oriented toward applied researchers, in that it emphasized good data visualization and diagnostic practices in model building. What it lacks, however, are examples developed in a computing environ-ment that would allow students of the book to follow along for themselves. An R and S-PLUS Companion to Applied Regression fills this gap. S-PLUS and R are, respectively, commercial and free implemen-tations of the S statistical computing language. R is a very successful open-source software project that has shown rapid and sustained development over the past few years. For instructors, it has three main benefits. First, it is freely available for all the operating systems students are likely to use, including Windows, Macintosh, and Linux. (It can be downloaded a