Packages are the fundamental units of reproducible R code. They include reusable R functions, the documentation that describes how to use them, and sample data. This practical book shows you how to turn your code into packages that others can easily download and use. By applying author Hadley Wickham's philosophy of package development, you'll learn to focus on what you want your package to do, rather than think about package structure. You'll also work with Hadley's devtools package, a suite of R functions for automating common development tasks. Devtools encapsulates best practices of package development that he's learned over the years. With this book, Hadley will show you how to use devtools to develop your own packages. * Create R packages that save you time and are easy for others to use * Understand the most common and useful components of packages * Start with the basics and improve your package writing over time * Automate anything you can and do as much as possible with functions * Streamline your development process with devtools * Learn from a well-respected member of the R community who created 30 R packages including ggplot2