When David Roth was asked to perform in impromptu circumstances, he would typically perform the following sequence of five routines. A close examination of this selection of material can serve to reveal a number of significant lessons. I came to understand the theory behind all this in the course of my study of magic in general, coin magic in particular, and David Roth’s magic as an exemplar. Roth’s choices can readily be seen as theory in action, and an answer to the question: Why study theory?