We feel, therefore we are. Conscious sensations ground our sense of self. They are crucial to our idea of ourselves as psychic beings: present, existent, and mattering. But is it only humans who feel this way? Do other animals? Will future machines? Weaving together intellectual adventure and cutting-edge science, Nicholas Humphrey describes his quest for answers: from his discovery of blindsight in monkeys, and his pioneering work on social intelligence, to breakthroughs in the philosophy of mind. The goal is to solve the hard problem: to explain the wondrous, eerie fact of “phenomenal consciousness” – the redness of a poppy, the sweetness of honey, the pain of a bee-sting. What does this magical dimension of experience amount to, what’s it for, and why has it evolved? He presents here, in full for the first time, a plausible solution, It implies that phenomenal consciousness, far from being primitive, is a relatively late and sophisticated evolutionary development. The implications, for the existence of sentience in nonhuman animals, are startling and provocative.