I discuss the volume edited by Andrea Falcon and Stasinos Stavrianeas which includes a new Greek text of Aristotle's De incessu animalium (On the Progression of Animals) by Pantelis Golitsis and nine interpretative essays. Since the De incessu is largely uncharted territory, my main goal is to introduce some of the exegetical debates initiated in this volume and to hint at points of departure for further discussion. I pay particular attention to the famous principle that nature does nothing (...) in vain. (shrink)