I would like to state openly and humbly that this book should not be followed for biblical teachings or as biblical doctrine. It has been translated into Tamil solely for the purposes of awareness and research.
This Tamil translation has been made using the English edition by Moses Samuel. Several Hebrew scholars have noted that this English translation is excellent. Some of them include: Rabbi H. V. Nathan, Professor Samuel H. Turner, Professor George Bush, and Professor Isaac Nordheimer.
Both Professor Turner and Professor Bush specifically pointed out that its original text was written in "Rabbinical Hebrew" with an intermixture of biblical idioms.
The name of the original Hebrew book is Sefer haYashar (ספר הישר). This translates to "The Book of the Upright" or "The Book of Jasher." It is said that this book is mentioned in two places in the Bible: Joshua 10:13 and 2 Samuel 1:18.
Joshua 10:13: 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.
2 Samuel 1:18 Also he bade them teach the children of Judah the use of the bow: behold, it is written in the book of Jasher.
The author of the original Hebrew book remains unknown.