The readers of this book need to have some knowledge on basic R programming along with basic knowledge on statistical analysis and graphics. Though most of the graphs discussed in this book are very common and easy to understand, there are some recipes where readers need to have statistical knowledge. All of the examples in this book have been created with R Version 3.0.2, so readers can reproduce all of the examples with this version or higher. However, it's possible that, if a reader uses a lower version, most of the examples will still run but not all.