This paper proposes a general principle of topic resources as a key principle of conversation. The first section of the paper offers a discussion of the notion of cohesion as a condition in which interactants perceive that their utterances are related to one another and presents the "given-new" strategy (in which the interactants indicate what elements in an utterance are built upon prior discourse and which are without such antecedents). It then suggests this strategy as a perspective from which to analyze the sources of cohesion between utterances and to monitor changes in conversational topics. The second section details the distinction between the elements in an utterance that have the status of "given" and those that have the status of "new." The third section draws upon the"given-new" distinction to identify specific procedures for establishing the cohesion of utterances within conversations and to formulate the topic resources principle. The fourth section contains a discussion of the main implications of this principle. (FL)