There are at least two books on this subject:
They Have a Word for It: A Lighthearted Lexicon of Untranslatable Words & Phrases by
Howard Rheingold, first published in 1988; and
The Meaning of Tingo…and Other Extraordinary Words from Around the World by
Adam Jacot de Boinod, published in 2005.
Notwithstanding the subtitles, the latter is actually more lighthearted than Rheingold’s book, which goes into more depth in terms of the nuance and context for each word, as well as aiming to add to the reader's working
vocabulary. Both, however, make excellent
lavatorial reading material.
As other noders have pointed out, it is possible to translate supposedly ‘untranslatable’ words, or to convey the meaning of such a word using multiple words. However, there is a world of difference between, say, ‘Drachenfutter’, a German compound-noun which translates literally as ‘dragon fodder’ and which describes a peace offering for a woman from a guilty man (e.g. a bunch of flowers), a meaning immediately graspable by most Westerners, and a word such as ‘aware’ (pron. ah-WAH-ray), Japanese for ‘the feelings engendered by ephemeral beauty’,* which may arguably require an enhanced understanding of Japanese culture in order to fully appreciate its native and original meaning, albeit one may easily gather a functional approximization in Western terms.
Rheingold’s introduction touches briefly upon the Sapir-Whorf hypothesis and words for colour, and it is this aspect – the idea that language may influence culture and thought patterns or vice versa, a theory supported (in either direction) by the subtle personality changes one undergoes when speaking a non-mother tongue - which makes supposedly untranslatable words interesting as players in this ongoing chicken and egg-style debate.
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* Rheingold, H., They Have a Word for It, Sarabande Books, USA, 2000, p99
http://www.themeaningoftingo.com/