In this paper I propose that the indirect object (IO) of verbs and constructions that lack an AGENT occupies a pre-verbal position in order to function as sentence TOPIC. I assume that a TOPIC is preferably an argument endowed with agentive properties (Dowty 1991), because they reflect the cognitive attributes of a prototypical TOPIC (van Oosten 1986). In sentences that lack an AGENT, the IO has agentive properties and therefore it is preferred to the subject as sentence TOPIC. My analysis can thus explain the link between the pre-verbal position and the agentive properties of the IO. Furthermore, I show that the interpretive differences (contrastive or not contrastive) between the IO of non-agentive constructions and the direct object (DO) of transitive verbs in preverbal position are due to the fact that, while the former is a prototypical TOPIC, the latter is not. The DO is in fact chosen by the speaker as TOPIC precisely to contrast it with another TOPIC in the discourse.