The Dictionary of Untranslatables, first published in 2014, is currently still available in hardback and other formats. It needs a presence because it is primarily a tool that is an almost essential component of any technical philosophical discussion. At 1344 A4 pages it has an object quality that also meets its purpose for the non-philosopher as a reminder of what philosophy is really about and what basic assumptions we need to unravel in almost any discussion of abstract concepts. The press release for the book describes it as ‘…an encyclopaedic dictionary of close to 400 important philosophical, literary, and political terms and concepts that defy easy—or any—translation from one language and culture to another. Drawn from more than a dozen languages, terms such as Dasein (German), pravda (Russian), saudade (Portuguese), and stato (Italian) are thoroughly examined in all their cross-linguistic and cross-cultural complexities. Spanning the classical, medieval, early modern, modern, and contemporary periods, these are terms that influence thinking across the humanities.’ This describes it well, but even the glittering list of awards that it has attracted does not do the book full justice as an example of the sort of clear authoritative scholarship that the humanities need. Originally published in French, the Dictionary of Untranslatables is a massive and admirable undertaking by leading scholars and authorities to codify the possibly simultaneous meanings of the more technical terms that are essential – or seem essential -– in philosophical writing. Many of these words are also used professionally by academics in the sciences, arts and humanities in the sharing of ideas. But words such as ‘time’ ‘imagination’ ‘feeling’ ‘people’ pathos’ etc. it is claimed are untranslatable. The entry for ‘History’, for example, addresses the Dutch, German, Greek, Italian and Latin words tracing the path of the idea through its various translations. Despite its widespread use there is, of course, no definitive translation because, as the various versions show, it is an untranslatable term requiring clear definition before it is used. Within the ten pages it uses to follow this pathway of the concept of history through different languages there are a number of explanatory ‘boxes’ in which cognate branches such as metahistory and historiography etc. are laid out in clear authoritative language In the process of its efforts to reveal the locus of a concept, there is an awareness of language as partial and subject to wear and tear, Hartog and Werner, who are responsible for this entry open the translation with a question. ‘The path from Greek historia to the French histoire […] seems simple and direct. History was always history! One clue, however, should put us on our guard: why did the German end up distinguishing between Historie (a clear translation of the Latin historia) from Geschichte (referring to what has happened but also to the recounting we give of the study of the past - “History” with a capital H)?’ (p.439). This discursive tactic runs through many entries as the contingencies of translation are revealed to have much wider effects on our understanding of ourselves. All this is done with the generosity and grace that often follows confident authority. The fundamental problem that the Dictionary of Untranslatables tackles rests most squarely in the domain of philosophy and the philosophy of translation but that should not deter other readers. In the first place there is sublime pleasure to be gained from engaging with words for ideas in a raw and weightless state as their meanings are briefly freed from the gravitational pull of habitual language. There is also much to be said for the sheer joy and confidence of much of the writing in the book. Perhaps most of all in the context of the Leonardo project its presence is a constant reminder that as we work across and between disciplines, we cannot assume that we are using the same terms to mean the same things. The Dictionary of Untranslatables is and clear and cathartic read that cleanses the palette after much that is served up. It is still available in hard copy and recommended as a valuable fixture on the desk and an important tool for us to rehearse our ways of thinking as well as reminder that in dealing with complex topics there is a great pleasure to be had in being clear. There are also a number of other reviews online including two especially helpful ones by Lucie Mercier (https://www.theoryculturesociety.org/blog/review-barbara-cassin-et-al-dictionary-of-untranslatables and Michael Kinnucan (https://www.asymptotejournal.com/criticism/barbara-cassin-dictionary-of-untranslatables-a-philosophical-lexicon/).