The Targum Yonason is a fairly standard commentary on the Torah (we are only discussing the Torah one). Now, as most are aware, in fact this is not from Yonason but instead is more correctly called Targum Yerushalmi (Jerusalem Targum). In academic circles it is referred to as Pseudo-Jonathon. In all likelihood, the original name was in fact Targum Yerushalmi but was abbreviated as ת”י and thus mistakenly expanded to be תרגום יונתן and not the correct תרגום ירושלמי. Various editions of this commentary have been published and you can find a listing in Kasher’s Sa’arei HaElef. (you can see a bibliography of translations here and more stuff here.)

Be that as it may, there is much discussion about the content of this Targum. For instance, perhaps most famously, this Targum “translates” the prohibition against cross-dressing as prohibiting women from donning Tallit and Teffilin. While there are some complete works on the Targum (see the lists in Kasher, supra, as well as Kasher’s discussion on the Targum generally in Torah Shelemah, and Kressel, Ma’ada haMikrah), most of the discussion which touches on this Targum appears in books which are not directly related to this Targum. This makes it difficult to locate but now this has been remedied with a new edition (thus far on Berashis, Shemos, and most recently Devarim) which collects just about everything on this Targum.

The work is titled Sa’resi Ba’Midinah and is edited by R. Henoch Levine.* As mentioned above, a major difficulty is locating the discussions on this Targum, this edition has uses hundreds of books and collected the relevant material for the reader. Additionally, an especially nice touch and one lacking (if you are sensitive don’t read the rest of the sentence) in many seforim today, it includes a bibliography of all the works used. This bibliography is not just a list of titles but even provides which edition was used to make it easy for the reader to check the source themselves. Further, the author as well as the topic (many books have the same name) are included to further insure ease of location of the sources. The breadth of sources is astounding. Further, a index which includes Tanakh, Shas, Midrash, and Shulhan Arukh, is included as well. All of this is printed on nice paper in clear text. The Targum is included as well as the text of the Torah, Onkelos, Rashi, and Toldot Aaron.

As for the Targum itself, according to the introduction (which appears in the Shemot volume) the editor attempted to correct the text. But, it is unclear how or what he did on that front. There are critical editions of this work (see the sources supra) but I can not tell if he used them.

The one shortcoming appears in the introduction. There, the editor, using the book Yanchanu which is devoted to defending the notion that this targum is in fact from R. Yonason, attempts to show that this work is truly from R. Yonason b. Uzzeil the Tanna. He spends the bulk of the introduction on this task. As we know this has been shown to be wrong. Additionally, what is particuarly disturbing is one manner in which the editor (recounting as it appears in Yanchanu) “proves” his point. The editor marshalls R. Tzvi Hirsch Chayes (Maharetz Hiyot), the editor alleges, the Maharetz in a footnote also allows the author is in fact the Tanna. The citation is to a footnote in Minhat Kinot, Mahritz’s defense of Orthodox Judaism against Reform Judaism. (there is no pagination in the introduction but it appears in the second page of the introduction) The footnote in fact is not really on point. But setting that aside, Maharetz wrote an entire work discussing the various Targumim, and specifically discusses the Targum Yonason. Maharetz says explictly the commentary on the torah is NOT from the Tanna. (See Imrei Binah no. 4). Maharetz is not the only “traditional” scholar to argue this, a bit earlier, R. Shlomo Chelm, author of the Merkevet HaMishna (a fascinating character in his own right) also says this Targum is not from the Tanna. (Merkevet HaMishna, Ma’chelet Assurot, 1:8). Thus, while a quote in isolation may support the notion Yonason was in fact the author, the R. Chayes himself was clearly of the opinion this Targum was not from Yonason.

In the US, the books are available at Beigeleisen and possibly others and in Israel try Girsa.

*[To make this clearer, as there seems to be some confusion, I will first discuss the positive points of this work and then discuss some drawbacks. Perhaps this format will enable anyone who doesn’t want to know about the drawbacks to stop reading or, if need be, cover over the final paragraph.]