This chapter provides an introductory overview of biosemiotics—the study of meaning-making mechanisms in the living world. Biosemiotics is a study of those types of sign processes that are not based on human language. We describe history of the field both before 1960 (focussing particularly on the work of Jakob von Uexküll), and after this date (in the framework of institutionalized semiotics). In addition to the phenomena and role of meaningful communication (including autocommunication, intraspecies, and interspecies communication) in the organization and design of organisms and communities, the problems as the semiotic thresholds, models of semiosis, and the role of semiosis in development and evolution are dealt from the biosemiotic point of view, i.e. on the basis of semiotic modelling.