Erich Boleyn originally designed and implemented GRUB.

VaX#n8 (real name unknown) wrote shared_src/fsys_ext2fs.c.

Heiko Schroeder rewrote shared_src/stage1.S to be more readable.

The following authors assigned copyright on their work to the Free
Software Foundation:

Gordon Matzigkeit adopted GRUB into the GNU Project.  He fixed several
bugs, added symbolic link support to shared_src/fsys_ext2fs.c, and
began the implementation of /sbin/grub.

OKUJI Yoshinori contributed many bugfixes and new features, such as
working LBA support, and /sbin/grub support for configuration files.

Peter Astrand added support for a color menu.

Pavel Roskin contributed many bugfixes and new features, such as FreeBSD
support in the grub shell, and configure process cleanups.