Many are the paths to the history of theories we could follow to discuss the nature of metaphor. And many linguistic issues puzzling modern linguistic tradition were first stated by Aristotle. Since Greek antiquity, a vast array of approaches and studies have been devoted to metaphor. And it is not the aim of this paper to trace the paths followed and the goals reached over the centuries. The present paper sets out with a twofold purpose in mind. On the one hand, metaphor will be shown to be much more than a rhetorical figure and a textual embellishment, since who writes strongly adheres to the theoretical commitment according to which metaphor is one of the powerful heuristic tools our mind exploits to structure human reasoning. On the other hand, metaphor will be discussed with reference to the practice of translation with the aim of paving the way for a cognitive model of translation planted on the theories of Mental Spaces and Conceptual Integration. A model will be proposed – the Translational Projection Hypothesis – which is meant to describe the cognitive elaboration translators experience when transferring meaning from the source text into the target text.