Anthropomorphism in the study of animal behaviour has been a hobby-horse of mine for more than fifty years. During those years the pendulum has swung both ways between anthropomorphism and behaviourism. I was enjoined long ago to develop my concern with this problem into a book, but I could ill afford the concentration it demanded; and doing experiments was anyway much more fun than writing. Perhaps it is not a bad thing that the book has had to wait so long to be written, brief though it is, since of course my thoughts on the subject have meanwhile been changing, most of all in the last few years. But at the same time the status of anthropomorphism itself has been changing, too. Once a live issue, a butt for behaviourists, it now gets little more than an occasional word of consensual disapproval (and exceptionally a spirited defence). What now gave me pause was doubt that any readers would be found for a book that criticized anthropomorphism. Most people might suppose, nowadays, that a book with that word in its title could only be flogging a dead horse. I have to thank three strategically placed people for convincing me that a book on the particular lines of this one would be worth the effort: Vince Dethier, Jeffrey Gray and Pat Bateson, the last being good enough to read and criticize the whole manuscript.