The Book of Jasher Frá tíma Gamla testamentisins Dauðahafshandritin .

The Book of Jasher
Chapters 1 - 2

            The Book Of Jasher, or Sepir Ha Yasher in Hebrew, contains over 150,000 words or the equivalent of about 1/5 of the entire text in the 66 books of the Authorized King James Bible. It is an accepted ancient Hebrew manuscript, and is mentioned twice in the Bible. Although most people believe that a man named Jasher wrote the book, the Hebrew word Jasher means straight or upright, therefore, the translated name of this book would be The Book of the Straight or Upright, or the Upright or Correct Record.  
            We find mention of Jasher in Joshua 10: 12 Then spake Joshua to the LORD in the day when the LORD delivered up the Amorites before the children of Israel, and he said in the sight of Israel, Sun, stand thou still upon Gibeon; and thou, Moon, in the valley of Ajalon.13 And the sun stood still, and the moon stayed, until the people had avenged themselves upon their enemies. Is not this written in the book of Jasher? So the sun stood still in the midst of heaven, and hasted not to go down about a whole day. 14 And there was no day like that before it or after it, that the LORD hearkened unto the voice of a man: for the LORD fought for Israel.  The verse referred to in Joshua is Jasher 88:63. 
            Jasher is also mentioned in 2 Samuel 1:17 And David lamented with this lamentation over Saul and over Jonathan his son: 18 (Also he bade them teach the children of Judah the use of the bow: behold, it is written in the book of Jasher.) The Book of Jasher provides insight into the historical period from creation through the time of Joshua. This book has never actually been "lost"; it has been kept from public view for centuries and has been published very rarely until now. The Book of Jasher was said to have been found in Jerusalem during its capture by Titus. In 1840, many experts proclaimed the English translation of The Book of Jasher, in general, a correct translation from the Hebrew.
            The Book of Jasher also contains a more extensive and complete genealogical history than the Old Testament books of the King James Bible, along with some major insights into major Old Testament characters and the early biblical history.  We include this book in our online collection, with the confidence that it is one of the most valuable ancient Hebrew writings, equal in status to the other Old Testament books organized by the Emperor Constantine in the 4th Century AD.  

http://www.sacred-texts.com/chr/apo/jasher/index.htm