For those who can not work with the original French, this dictionary is the current standard work of Yiddish lexicology. Yiddish-German dictionaries and there are some, but unfortunately they are less outdated extensive and hopeless. Although the German Yiddish working on a corpus-based Yiddish-German large dictionary. Until that is done, however, can probably go even a few decades into the country.
If you want to get a taste of the diversity of the entries in this Yiddish-English Dictionary, should visit the website of "Yiddish Daily Forward". There you double click on a Yiddish word, the English translation will be published in this book. Very awesome!