Communication is a basic behaviour, found across animal species. Human language is often thought of as a unique system, which separates humans from other animals. This textbook serves as a guide to different types of communication, and suggests that each is unique in its own way: human verbal and nonverbal communication, communication in nonhuman primates, in dogs and in birds. Research questions and findings from different perspectives are summarized and integrated to show students similarities and differences in the rich diversity of communicative behaviours. A core topic is how young individuals proceed from not being able to communicate to reaching a state of competent communicators, and the role of adults in this developmental process. Evolutionary aspects are also taken into consideration, and ideas about the evolution of human language are examined.