Concise Bible Dictionary:
An ancient recension of the five books of Moses. Though it had been mentioned by some of the early fathers, it was not till about A.D. 1616 that a MS copy of it was discovered. At first it was considered by some as far superior to the Hebrew Pentateuch, but when other copies came to light (there are now about twenty) and they were examined more carefully, the thought of its superiority was not maintained; it is now regarded only as a copy of the Hebrew, though it agrees with the LXX in many places where that differs from the present Hebrew text. The Pentateuch which the Samaritans called “The Law” is all they have of the Old Testament. The characters in which it is written, by being compared with ancient coins, etc., are judged to be more ancient than the square Hebrew letters now in common use. The origin of it may have been a copy of the Pentateuch secured by the Israelites on the division of the kingdom. The Paris and the London Polyglots give the text in full.