Most of us tend to think of the fourth century BC as the time when a reasonably standardized vocabulary for rhetoric developed, and along with it an increasingly selfconscious and systematized notion of the TE/XNH of persuasion. There is certainly some truth in this; but it is also very likely that, if we simply had more evidence from the fifth century, particularly about the sophists, we would have to reformulate significantly our understanding not only of the development of rhetoric but of the entire contemporary intellectual landscape as well. O'Sullivan's monograph, a revision of a 1986 Cambridge PhD dissertation, cannot of course conjure up a new body of fifth-century evidence, but it does make us rethink many of the common presumptions about the early development of Greek rhetorical theory.