Jastrow's Aramaic lexicon of the Targums, Talmud, and Midrash has been given short shrift for a long time. Eerdmans was printing a new edition a few years ago, but then it turned out to be just a reprint. The condition of the text has not been good.

Logos has taken it on
http://www.logos.com/products/prepub/details/5261