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Sefer haYashar, Hebrew ספר הישר (also transliterated Sēper haiYāšār), "Book of the Upright", often only half-translated into English as Book of Jasher or as Book of Jashar.
There are a number of works with this name:
Sefer haYashar (Biblical references): A book mentioned in Joshua 10:13 and 2 Samuel 1:18.
Rabbinical Treatises:
Sefer haYashar (Amoraim): A collection of sayings of the sages from the Amoraim period (1st and 2nd centuries) mentioned by Seymour J. Cohen in the introduction to his Sefer Hayasher. Not known to be still in existence.
Sefer haYashar (Rabbenu Tam): A famous 12th century treatise on Jewish ritual and ethics by Rabbenu Tam.
Sefer haYashar (Rabbi Levita): The title of a moral treatise written by Rabbi Shabbatai Carmuz Levita in 1391 and preserved in a Vatican manuscript according to Edgar J. Goodspeed (in Modern Apocrypha, Famous Biblical Hoaxes [The Beacon Press, Boston, 1956])
Sefer haYashar (Rabbi Ha-Yevani): A moral treatise of the 13th century published as Ha-Yewani Zerahiah, Sefer Hayashar, The Book of the Righteous, ed. and transl. by S. J. Cohen (New York, 1973).
Sefer haYashar (Rabbi Jonah ben Abraham): A 14th century work by Rabbi Jonah ben Abraham of Gerona mentioned by Seymour J. Cohen in his Sefer Hayashar. Not known to be still in existence.
Sefer haYashar (midrash): A book of Jewish legends covering the period from the creation of man to the first wave of the conquest of Canaan, usually dated to about the 13th century, seemingly intended to represent the book referred to in Joshua and 2 Samuel.
Book of Jasher (Pseudo-Jasher): An 18th century forged translation of the lost book of Jasher attributed to Alcuin.
Book of Jashar by Benjamin Rosebaum. A fictional translation of the supposed Book of Jasher mentioned in 2 Samuel.
Jasher entertained the officers largely, as she was hospitable by nature, and liked to have presentable men about her for flirting purposes.
Jasher after the commotion caused by the crime, as she wished to speak to her about the same; but on each occasion the widow proved to be absent in London.
Jasher in a tea-rose tea-gown for afternoon tea - she always liked to be in keeping - rang for that beverage dear to the feminine heart, and lighted a rose-shaded lamp.