Aharon Dolgopolsky was the leading authority on the Nostratic macrofamily. It is with great sadness that we announce that he passed away on 20 July 2012. His 'Nostratic Dictionary' presented here is, of course, something very much more than a dictionary. It is the most thorough and extensive demonstration and documentation so far of what may be termed the Nostratic hypothesis: that several of the world's best-known language families are related in their origin, their grammar and their lexicon, and that they belong together in a larger unit, of earlier origin, the Nostratic macrofamily. It should at once be noted that several elements of this enterprise are controversial. For while the Nostratic hypothesis has many supporters, it has been criticized on rather fundamental grounds by a number of distinguished linguists. The matter was reviewed some years ago in a symposium held at the McDonald Institute, and positions remain very much polarized. It was a result of that meeting that the decision was taken to invite Aharon Dolgopolsky to publish his Dictionary - a much more substantial treatise than any work hitherto undertaken on the subject - at the McDonald Institute. For it became clear that the diversities of view expressed at that symposium were not likely to be resolved by further polemical exchanges. Instead, a substantial body of data was required, whose examination and evaluation could subsequently lead to more mature judgments. Those data are presented here, and that more mature evaluation can now proceed. This edition is Dolgopolsky’s final one as submitted in January 2012. It is revised and augmented by the author but remains unedited and unproofed due to his unfortunate death.