Ethology, or how animals relate to their environments, is currently enjoying increased academic attention. A prominent figure in this scholarship is Gilles Deleuze and yet, the significance of his relational metaphysics to ethology has still not been scrutinised. Jason Cullen's book is the first text to analyse Deleuze's philosophical ethology and he prioritises the theorist's examination of how beings relate to each other. For Cullen, Deleuze's Cinema books are integral to this investigation and he highlights how they expose a key Deleuzian theme: that beings are fundamentally continuous with each other. In light of this continuity then, Cullen reveals that how beings understand each other shapes them and allows them to transform their shared worlds.