R is provided with a command line interface (CLI), which is the preferred user interface for power users because it allows direct control on calculations and it is flexible. However, good knowledge of the language is required. CLI is thus intimidating for beginners. The learning curve is typically longer than with a graphical user interface (GUI), although it is recognized that the effort is profitable and leads to better practice (finer understanding of the analysis; command easily saved and replayed). The user interface remains the biggest difference between R and S-PLUS, since the latter implements a very sophisticated GUI. A fraction of the R users are asking for, and would probably benefit from a R GUI, mainly, occasional users and some teachers. R is open and communicating. Several projects develop or offer the opportunity to develop alternate user interfaces. They are presented here. A Special Interest Group mailing list (R-SIG-GUI) exists also to freely discuss concerned issues. You can subscribe here. The R (GUI) Wiki is also there to exchange information and ideas related to the use of R GUIs and to start using R.Last update: 16 Augustus 2010, by Philippe Grosjean.