Partial Differential Equations III : Nonlinear Equations R a free and open source program is one of the most powerful and the fastest growing statistics program. Microsoft Excel is the most widely used spreadsheet program but many statisticians consider its statistical tools too limited. In this book the authors build on RExcel a free add in for Excel that can be downloaded from the R distribution network. RExcel seamlessly integrates the entire set of Rs statistical and graphical methods into Excel allowing students to focus on statistical methods and concepts and minimizing the distraction of learning a new programming language. Data can be transferred between R and Excel the Excel way by selecting worksheet ranges and using Excel menus. Rs basic statistical functions and selected advanced methods are available from an Excel menu. Results of the computations and statistical graphics can be returned back into Excel worksheet ranges. RExcel allows the use of Excel scroll bars and check boxes to create and animate R graphics as an interactive analysis tool. The book is designed as a computational supplement to introductory statistics texts and the authors provide RExcel examples covering the topics of the introductory course. Richard M. Heiberger is Professor of Statistics at Temple University. He participated in the design of the S Plus and R linear model and analysis of variance functions while on research leave at Bell Labs. He is the author of and contributor to various R packages. He is an Elected Fellow of the American Statistical Association (ASA) and the Chair Elect of the ASA Section on Statistical Computing. Erich Neuwirth is Professor of Computer Science at the University of Vienna and was formerly Professor of Statistics. He is the author of RExcel and author of and contributor to various R packages. He is coauthor of Mathematical Modeling with Excel winner of the European Academic Software Award 1996 (for a project combining mathematics and music) and Associate Editor for Computational Statistics and Journal of Statistical Software.