R is a powerful language and software environment for statistical and graphics calculation. It is an open-source program, which means it is free to use, and its popularity reflects a shift in statistical computing and visualization output. The importance of R as a statistical language in today’s data-rich environment is its utility in analyzing and visualizing large data sets with the strong backup of its community of users and developers. The popularity of R continues to grow and achieve a global reach not only with academic researchers and programmers but also with private companies and local and national governments. After reviewing the history of statistical computing and open-source software, this entry focuses on open-source R and the solutions it provides for analyzing large data sets.