Translation is a particular form of writing under constraint: the translator is bound to write the original text in another language. This restricted definition of translation serves a guiding thread for the thesis, which marks out the limits of translation, or what translation cannot do, and to determine what translation can do, exemplarily. The deficiency of translation, like that of the lipogram, is assured by the constraint that distinguishes it from other forms of writing, other transformational processes. Translation always fails: its first rule guarantees it (which means that failure is also the condition of translation's success; or, simply, of translation). Translation is therefore always possible: again, like the lipogram, translation is all about finding ingenious ways of saying the unsayable. What, then, is untranslatable? Nothing, insofar as the recognitiono f the untranslatabled ependso n translationh aving alreadyt akenp lace.A s Sigmund Freud knew, it is only in the context of translation we can think productively about untranslatability, and the particular problems that jokes, mistakes, poems and literature more generally present for the translator. Writing according to a particular, imposed rule (such as the unconsciousm echanismo f condensationo r Raymond Roussel's consciously applied procýdj) forces language out of its usual functioning, mines untapped resources, exploits usually unnoticed homonyms and homographs, sometimes in order to produce remarkably economical expressions. The application of these rules contributes to the untranslatability of Jacques Derrida's texts, which serve as a kind of case study. We are dealing with the untranslatable when translation becomes explanation, commentary or scholarship. We have, therefore, something like translation (as a form of writing under constraint) setting the limits for translation (as a form of writing under constraint) can do. The way in which a language has been defamiliarised, foreignised or, as Gilles Deleuze puts it, minorised cannot be translated. For Deleuze, this minorisation finds its greatest expression in literature. Yet, as Walter Benjamin was aware, the specific task of translation (as a regulated operation that brings languages into contact with one another) is precisely to initiate that process of defamiliarisation: translation and literature, therefore, are bound together in a common project of linguistic regeneration. This is why, in the end, the question of translation is also the question of literature.