The present book originated as a doctoral dissertation a t the University of Zurich .In the present study I shall establish the idiom as a functional element of language. My approach will thus be based on a pragmatic view of language, as I have outlined below. Idioms are seen as a special category of lexical items which are not only determined through their structure, but which also show a specific type of behaviour in lan guage use. By analysing this behaviour I hope to create a pragmatic model for English idioms and thus to provide a basis for a theory of idioms as a phenomenon of natural language. The study consists of two major parts, the theoretical framework and a pragmatic analysis of conversational data.