Rashi

Klalim

Fundamentals

1. Rashi, colloquially known as "Kuntress," always takes the simplest Peshat of the Gemara, even if it's not in line with the accepted Halacha - even a Hava Amina rejected by the Gemara itself later on!
2. Along the same lines and by no means in disparagement of Rashi, the Radbaz alerts us that Rashi is primarily a Mefaresh, not a Posek, so much so that he doesn't even register as a Shitah when deciding a Machloket between Rishonim, such as the Rosh and Rambam., though some disagree. Although some are concerned for Rashi's Kavod, the point is that Rashi himself didn't intend to teach Halacha LeMaaseh with his commentary. Of course, if he explicitly writes a ruling, it is intended as such.
3. In his inimitable and calculated pithiness, Rashi negates numerous difficulties with the understanding of the Gemara with just a few words. This is very much part of Rashi's claim to fame. With just an extra letter, Rashi hints to numerous chiddushim.
4. Rashi made three editions of his commentaries, which accounts for the apparent contradictions in what we have on the page and what Tosafot is arguing on.
5. One cannot pose the tradition of the Geonim as a question on Rashi - "Gavra Agavra KaRamit?!"
6. Whenever Rashi uses the words כלומר he is offering that particular interpretation where one would have been able to offer an alternative one.
7. When Tosafot attacks Rashi with a series of difficulties from later Masechtot, one could argue Rashi assumes the Gemara at this point isn't working with them in mind.
8. The acronym 'לוי"ה' refers to Rashi's teacher, R' Yitzchak HaLevi.

Other Works

1. Rashi also wrote a commentary on Midrash Rabbah, a Halacha Sefer known as Sefer HaPardes, and She'elot uTeshuvot. He also had a hand in Kabbalah. A Talmid condensed and organized Sefer HaPardes into "Likutei Pardes," which is quoted often by Poskim by its acronym "Lamed Peh."
2. Machzir Vitri was written by R' Simcha, a student of Rashi.

Works Not by Rashi

Just because a commentary is printed where one would think to find Rashi and even under the title of Rashi doesn't mean that it's actually by Rashi. Sometimes other commentaries were printed in its place and confusion set in as to the correct identity of the author. Below are some of the more well known issues of misattribution of commentaries to Rashi. Some claim that there are clear stylistic methods that can be used for these purposes of identification.

1. The commentary on Divrei HaYamim is not by Rashi, and on Iyov probably is.
2. The commentary on Pirkei Avot is probably by Rashi, as so many Rishonim refer to it has his.
3. The commentaries on the side of the Gemara where Rashi should be on Masechtot Meilah, Nazir, and Nedarim, are not by Rashi.
4. There is a debate among Acharonim if the commentary of Rashi on Masechet Ta'anit is authentic or not; it seems that many Acharonim assume that it indeed is by Rashi with some mistakes that crept in over time.
5. Rashi's commentary on Bava Batra after the beginning of Chezkat HaBatim seems to have never made its way to the hands of Rishonim like the Rashba.
6. The commentary Rashi on the Rif was compiled by a later student based heavily on Rashi.

Misc.

1. Peculiarly, the Ritva refers to Rashi as "Maran."
2. The Chida notes how Rashi is known as "Rashi" and not "Rash," because "Rash" means a poor person. For the same reason, the "Sar" MiKutzi is known as "Sar" and not "Rash."