Part I. The Setting of the Problem: 1 Devious intentions of monkeys and apes? Duane Quiatt; 2. What the vocalizations of monkeys mean to humans and what they mean to monkeys themselves Robert M. Seyfarth; 3. Category formation in vervet monkeys Dorothy L. Cheney; Part II. Theoretical Preliminaries: 4. The strange creature Justin Leiber; 5. Vocabularies and theories Rom Harre; 6. Ethology and language Edwin Ardener; 7. Must monkeys mean? Roy Harris; 8. The inevitability and utility of anthopomorphism in description of primate behaviour Pamela J. Asquith; Part III. Steps towards a solution: 9. 'Language' in apes H. S. Terrace; 10. Social changes in a group of rhesus monkeys Vernon Reynolds; 11. Categorization of social signals as derived from quantitative analyses of communication processes M. Maurus and D. Ploog; 12. Experience tells Eric Jones and Michael Chance.