||Rashi's prayer book assembled from three manuscripts by the editor. The work is a source of Ashkenazi customs and rituals as practices by Ashkenazi Jewry in the 12th century.
The special character of the books of "the school of Rashi" as halakhic collections caused them to pass through many hands, involving additions and omissions, so that the traditions and the practices have become confused. The many parallels existing among these books themselves show considerable differences. Despite the fact that Rashi's main aim in his commentaries was not to determine the halakhah, practical halakhic rulings are scattered here and there, and at times even at length, and he was regarded as a halakhic authority of the first rank in Germany during a very long period. In the same way as his commentary on the Talmud became the basis for all later literary activity in this field in France and Germany, even though his pupils and their pupils did not hesitate to query his comments, disagree with them, and suggest alternatives, so with regard to his other writings. They based themselves upon his oral teachings and his practices as testified to by those who witnessed them, though they did not hesitate to differ from him in practice from time to time.