GRUB can boot Linux as well as most other PC-based operating systems.
GRUB relies on various files in the /boot/grub directory to support reading from various types of filesystems.
GRUB is configured using /boot/grub/menu.lst (or /boot/grub/grub.conf on some distributions).
GRUB can be configured to present a text or graphical menu interface and also has a command-line interface.
Modifications to the GRUB configuration files do not require the grub command to be re-run (unlike LILO).