The Animal Side is a manifesto on the importance of animals for human thought. It attempts to characterize the importance, for human beings, of the fact that animals exist. Adopting a philosophical and poetic approach, the book seeks to show that animals' ways of inhabiting the earth are, for human consciousness, an expansion and an exploration of what philosophers and poets have tried to name by speaking of the Open.

Beginning with the story of an encounter with a deer on a road at night, the book proceeds by showing that, beyond the diversity of animal life and the ways animals differ from human beings, there is a "layer of the perceptible" on which we all draw, humans and animals alike, in our own ways. At present, however, this layer itself is at risk. Thus the book can also be read as a defense and illustration of animals' modes of
being, and as a plea for their survival.