Rabbi Shlomo Yitzhaki (February 22, 1040 – July 13, 1105), better known by the acronym Rashi, was a medieval French rabbi famed as the author of the first comprehensive commentary on the Talmud, as well as a comprehensive commentary on the Tanach. He is considered the "father" of all commentaries that followed on the Talmud and the Tanach. Acclaimed for his ability to present the basic meaning of the text in a concise yet lucid fashion, Rashi appeals to both learned scholars and beginning students, and his works remain a centerpiece of contemporary Jewish study.

His commentary on the Talmud, which covers nearly all of the Babylonian Talmud, has been included in every edition of the Talmud since its first printing in the 1520s. His commentary on Tanach, especially his commentary on the Chumash, is an indispensable aid to students of all levels. The latter commentary alone serves as the basis for more than 300 commentaries which analyze Rashi's choice of language and citations, penned by some of the greatest names in rabbinic literature. Rashi's surname Yitzhaki derives from his father's name, Yitzhak. The acronym is sometimes also fancifully expanded as Rabban Shel YIsrael (Teacher of Israel), or as Rabbenu SheYichyeh (Our Rabbi, may he live).

His fame later made him the subject of many legends. One tradition contends that his parents were childless for many years. Rashi's father, Yitzhak, a poor vintner, once found a precious jewel and was approached by non-Jews who wished to buy it to adorn their idol. Yitzhak agreed to travel with them to their land, but en route, he cast the gem into the sea. Afterwards he was visited by either a Bath Kol (Heavenly voice) or the prophet Elijah, who told him that he would be rewarded with the birth of a noble son "who would illuminate the world with his Torah knowledge." Legend also states that the couple moved to Worms while Rashi's mother was expecting. As she walked down one of the narrow streets in the Jewish quarter, she was imperiled by two oncoming carriages. She turned and pressed herself against a wall, which opened to receive her. This miraculous niche is still visible in the wall of the Rashi Shul.

According to tradition, Rashi was first brought to learn Torah by his father on Shavuot day at the age of five. His father was his main Torah teacher until his death when Rashi was still a youth. At the age of 17 he married and soon after went to learn in the yeshiva of Rabbi Yaakov ben Yakar in Worms, returning to his wife three times yearly, for the Days of Awe, Passover and Shavuot. When Rabbi Yaakov died in 1064, Rashi continued learning in Worms for another year in the yeshiva of his relative, Rabbi Isaac ben Eliezer Halevi, who was also chief rabbi of Worms. Then he moved to Mainz, where he studied under another of his relatives, Rabbi Isaac ben Judah, the rabbinic head of Mainz and one of the leading sages of the Lorraine region straddling France and Germany.

Rashi's teachers were students of Rabbeinu Gershom and Rabbi Eliezer Hagadol, leading Talmudists of the previous generation. From his teachers, Rashi imbibed the oral traditions pertaining to the Talmud as they had been passed down for centuries, as well as an understanding of the Talmud's unique logic and form of argument. Rashi took concise, copious notes from what he learned in yeshiva, incorporating this material in his commentaries.

He returned to Troyes at the age of 25, after which time his mother died, and he was asked to join the Troyes Beth din (rabbinical court). He also began answering halakhic questions. Upon the death of the head of the Beth din, Rabbi Zerach ben Abraham, Rashi assumed the court's leadership and answered hundreds of halakhic queries.

In around 1070 he founded a yeshiva which attracted many disciples. It is thought by some that Rashi earned his living as a vintner since Rashi shows an extensive knowledge of its utensils and process, but there is no evidence for this. Although there are many legends about his travels, Rashi likely never went further than from the Seine to the Rhine. The utmost limit of his travels were the yeshivas of Lorraine.

In 1096, the People's Crusade swept through the Lorraine, murdering 12,000 Jews and uprooting whole communities. Among those murdered in Worms were the three sons of Rabbi Isaac ben Eliezer Halevi, Rashi's teacher. Rashi wrote several Selichot (penitential poems) mourning the slaughter and the destruction of the region's great yeshivot. Seven of Rashi's Selichot still exist, including Adonai Elokei Hatzvaot, which is recited on the eve of Rosh Hashanah, and Az Terem Nimtehu, which is recited on the Fast of Gedalia.

Rashi died on July 13, 1105 (Tammuz 29, 4865) aged 65. He was buried in Troyes. The approximate location of the cemetery in which he was buried was recorded in Seder Hadoros, but over time the location of the cemetery was forgotten. A number of years ago, a Sorbonne professor discovered an ancient map depicting the site of the cemetery, which now lay under an open square in the city of Troyes. After this discovery, French Jews erected a large monument in the center of the square. A large, black and white globe featuring a prominent Hebrew letter, Shin (presumably for "Shlomo", Rashi's name). The granite base of the monument is engraved: Rabbi Shlomo Yitzchaki - Commentator and Guide. In 2005, Yisroel Meir Gabbai erected an additional plaque at this site marking the square as a burial ground. The plaque reads: "The place you are standing on is the cemetery of the town of Troyes. Many Rishonim are buried here, among them Rabbi Shlomo, known as Rashi the holy, may his merit protect us".

Rashi had no sons, but his three daughters, Miriam, Yocheved, and Rachel, all married Talmudic scholars. Legends exist that Rashi's daughters put on tefillin. While some women in medieval Ashkenaz did wear tefillin, there is no evidence that Rashi's daughters did so. Rashi's middle daughter, Miriam, married Judah ben Nathan, who completed the commentary on Talmud Makkot which Rashi was working on when he died. Their daughter Alvina was a learned woman whose customs served as the basis for later halakhic decisions. Their son Yom Tov later moved to Paris and headed a yeshiva there, along with his brothers Shimshon and Eliezer.

Rashi's oldest daughter, Yocheved, married Meir ben Shmuel. Their four sons were: Shmuel (Rashbam) (b. 1080), Yitzchak (Rivam) (b. 1090), Jacob (Rabbeinu Tam) (b. 1100), and Shlomo the Grammarian, who were among the most prolific of the Baalei Tosafos, leading rabbinic authorities who wrote critical and explanatory glosses on the Talmud which appear opposite Rashi's commentary on every page of the Talmud. Yocheved's daughter, Chanah, was a teacher of laws and customs relevant to women. Rashi's youngest daughter, Rachel, married (and divorced) Eliezer ben Shemiah.

Rashi's commentary on the Tanach, and especially his commentary on the Chumash, is the essential companion for any study of the Talmud at any level. Drawing on the breadth of Midrashic, Talmudic and Aggadic literature (including literature that is no longer extant), as well as his knowledge of grammar, halakhah, and how things work, Rashi clarifies the "simple" meaning of the text so that a bright child of five could understand it. At the same time, his commentary forms the foundation for some of the most profound legal analysis and mystical discourses that came after it. Scholars debate why Rashi chose a particular Midrash to illustrate a point, or why he used certain words and phrases and not others.

Scholars believe that Rashi's commentary on the Torah grew out of the lectures he gave to his students in his yeshiva, and evolved with the questions and answers they raised on it. Rashi only completed this commentary in the last years of his life. It was immediately accepted as authoritative by all Jewish communities, Ashkenazi and Sephardi alike. The first dated Hebrew printed book was Rashi's commentary on the Chumash, printed by Abraham ben Garton in Reggio di Calabria, Italy, 18 February 1475. (This version did not include the text of the Chumash itself.) Rashi wrote commentaries on all the books of Tanach except Chronicles I & II. Scholars believe that the commentary which appears under Rashi's name in those books was compiled by the students of Rabbi Saadiah of the Rhine, who incorporated material from Rashi's yeshiva. Rashi's students, Rabbi Shemaya and Rabbi Yosef, edited the final commentary on the Torah. Some of their own notes and additions also made their way into the version we have today.

Rashi exerted a decisive influence on establishing the correct text of the Talmud. Up to and including his age, texts of each Talmudic tractate were copied by hand and circulated in yeshivas. Errors often crept in: sometimes a copyist would switch words around, and other times incorporate a student's marginal notes into the main text. Because of the large number of merchant-scholars who came from throughout the Jewish world to attend the great fairs in Troyes, Rashi was able to compare different manuscripts and readings in Tosefta, Jerusalem Talmud, Midrash, Targum, and the writings of the Geonim, and determine which readings should be preferred. However, in his humility, he deferred to scholars who disagreed with him. For example, in Chulin 4a, he comments about a phrase, "We do not read this. But as for those who do, this is the explanation."

Some of the other printed commentaries which are attributed to Rashi were composed by others, primarily his students. In some commentaries, the text indicates that Rashi died before completing the tractate, and that it was completed by a student. This is true of the tractate Makkot, the concluding portions of which were composed by his son-in-law, Rabbi Judah ben Nathan, and of the tractate Bava Batra, finished (in a more detailed style) by his grandson, the Rashbam. There is a legend that the commentary on Nedarim, which is clearly not his, was actually composed by his daughters. Siddur Rashi, compiled by an unknown student, also contains Rashi's responsa on prayer. Other compilations include Sefer Hapardes, edited by Rabbi Shemayah, Rashi's student, and Sefer Haoraah, prepared by Rabbi Nathan Hamachiri.

Rashi's commentary on the Talmud continues to be a key basis for contemporary rabbinic scholarship and interpretation. Without Rashi's commentary, the Talmud would have remained a closed book. With it, any student who has been introduced to its study by a teacher can continue learning on his own, deciphering its language and meaning with the aid of Rashi.