Bourne Shell vs Bash Shell

[Bourne Shell]
Developed by Stephen Bourne at Bell Labs, it was a replacement for the Thompson shell, whose executable file had the same name—sh.
It was released in 1977 in the Version 7 Unix release distributed to colleges and universities.
Over the years, the Bourne shell was enhanced at AT&T.

[Bash Shell]
Bash is a Unix shell written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell (sh).
Released in 1989, it has been distributed widely as the shell for the GNU operating system and as the default shell on Linux and Mac OS X.
It has been ported to Microsoft Windows and distributed with Cygwin and MinGW, to DOS by the DJGPP project,
to Novell NetWare and to Android via GNU Bash Installer and various terminal emulation applications.

[Differences]
The Bash command syntax is a superset of the Bourne shell command syntax.
Vast majority of Bourne shell scripts can be executed by Bash without modification.
Bash's syntax has many extensions which the Bourne shell lacks.

reference:
http://en.wikipedia.org/wiki/Bourne_shell
http://en.wikipedia.org/wiki/Bash_(Unix_shell)