Answer:
   
   Rabbi Solomon ben Isaac (or: Shlomo Yitzhaki) is known by the acronym
   "Rashi". Rashi lived from 1040 to 1105 in Troyes, France.
   
   [In the www.scjfaq.org version, there is a picture of a Talmud Page to
   Illustrate This] In the Talmud, Rashi's Commentary is always situated
   towards the middle of the opened book display; i.e. on the side of the
   page closest to the binding. The semi-cursive font in which the
   commentaries are printed is often referred to as "Rashi script." This
   does not mean that Rashi himself used such a script, only that the
   printers standardly employ it for commentaries. And Rashi's were the
   commentaries par excellence to both the Bible and the Talmud. Rashi's
   Commentary, which covers almost the whole of the Babylonian Talmud,
   has been printed in every version of the Talmud since the first
   Italian printings.
   
   Rashi's commentary provides a full and adequate explanation of the
   words, and of the logical structure of each Talmudic passage. Unlike
   some other commentaries, Rashi does not paraphrase or exclude any part
   of the text, but carefully elucidates the whole of the text. Rashi
   also exerted a decisive influence on establishing the correct text of
   the Talmud. He compared different manuscripts and determined the
   readings that should be preferred.
   
   Rashi's commentary does not exist for every tractate of the Babylonian
   Talmud, and a few of the printed commentaries attributed to him were
   composed by others. In some instances, 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. It is
   also true of tractate Bava Batra finished (in a much wordier and
   detailed style) by his grandson, Rabbi Samuel ben Meir (Rashbam), one
   of the prominent contributors to the Tosafot. It is probably a sign of
   the success of Rashi's achievement that no subsequent scholar, until
   Rabbi Adin Steinsaltz in the late 20th century, tried to compose
   another comprehensive explanatory commentary.