In Metaphysics (Book 1) and Nicomachean Ethics (Book 6), Aristotle made a distinction between expertise, science, wisdom, and prudence. That distinction can provide a simple framework for understanding what I call the messy middle of transformation. The messy middle is the unknown, uncertain space between past and future, between theory and practice, that characterizes organizations in the process of becoming something new. To navigate the messy middle of transformation, leaders must understand how the different knowledge domains contribute to the transformation—and help their employees find a way to be part of the same conversation.