Summary: The mean value theorem of the elementary calculus keeps attracting the attention of mathematicians who ponder how to make its proof simple and elegant, how to generalize it, how to use it in proofs of other theorems, and, perversely, how to avoid it. This Monthly has carried dozens of articles in which the mean value theorem was the hero or the villain. We present three versions of the theorem in the form on an inequality, and boy, do they deliver a mean kick!