With regard to understanding the meaning of dialogue, as it returns to the educational scene, it is especially noteworthy that the so-called "teaching machine" has served to reveal two aspects of our educational situation. First, we can see now that the printed book was a "teaching machine" rather than a mere tool like the manuscript. We can also see now that the new "teaching machines" have less the character of book than of private tutorial dialogue. They have been badly named, somewhat after the fashion of the "horseless carriage."