At the Innotech conference, there was a TDD panel with Mary Poppendieck and 4 members of the local developer community (2 of them are my coworkers). Mary clarified that TDD is as old as software development itself. She relates that when she was coding assembly, she would create a testing framework to simulate the device she was writing for before she wrote any code. Then, every bit of code was written with automated tests. Here is a picture of the panel. From left to right there is Scott Bellware, Jeremy Miller, Jeff Smith, Bret Pettichord, and Mary Poppendieck.