Life with Unix says: Created the Bourne Shell. Wrote adb.

A Research Unix Reader says: Steve (Stephen R.) Bourne arrived at the time of v6, bringing Algol 68 with him. His definitive programs, the debugger adb, and the “Bourne shell,” although written in C, looked like Algol 68: Steve wrote DO-OD and BEGIN- END instead of { and }. Bourne also contributed macro constructs to the UNIX Circuit Design System