The aim of this book is to examine and challenge the boundaries so often drawn in philosophy, as elsewhere, between humans and other animals, drawing on philosophical, legal and scientific perspectives in order to question the legitimacy and utility of such distinctions and thereby to explore the moral and philosophical meanings of humanity and being human.

A century and half ago, Darwin's theory of evolution challenged the notion of absolute species boundaries, showing that humans were related to animals rather than created unique amongst living creatures and putting us on a continuum with other animals and indeed all life on earth.

Genetically, biologically, as moral subjects and even as moral agents, humans are a species of animal. What implications might this have for philosophical considerations of human nature, for the use of 'human' as a qualifier or distinguishing feature in moral, legal and social contexts, and for how we view ourselves, other creatures that exist now and creatures that might one day exist?