| base | The R Base Package |
| tools | Tools for Package Development |
| utils | The R Utils Package |
| grDevices | The R Graphics Devices and Support for Colours and Fonts |
| graphics | The R Graphics Package |
| stats | The R Stats Package |
| datasets | The R Datasets Package |
| methods | Formal Methods and Classes |
| grid | The Grid Graphics Package |
| splines | Regression Spline Functions and Classes |
| stats4 | Statistical Functions using S4 Classes |
| tcltk | Tcl/Tk Interface |
| compiler | The R Compiler Package |
| parallel | Support for Parallel Computation in R |