The making of models to encode knowledge is an intrinsic feature of human cognitive life. Signs, texts, codes, and various other representational forms are the direct outcomes of innate model-making systems. This book presents a methodological framework, developed from the field of biosemiotics, for studying semiotic phenomena as modeling processes. It presents a descriptive system for uniting semiotics and biology so that the "modeling instinct" can be studied in terms of its manifestations in various species. The book is written in an accessible textbook style, and can thus be used as a manual by both professional semioticians and students taking courses in semiotics, biology, and the communication sciences. It is composed in such a way that a broad readership can appreciate the fascinating research going on in a relatively unknown area of interdisciplinary study.