The Tosefta contains the rulings, sayings, and debates of the Tannaim and is arranged on the same pattern as the Mishnah in six orders and with the same tractates within the orders.
The name Tosefta would seem to suggest that the work is a supplement to the Mishnah but the problem of the relationship between the two works is far more complicated in that the Tosefta contains material not found in the Mishnah at all and it gives throughout the impression that it is a separate work standing on its own.
The problem is further complicated by the fact that while the Babylonian Talmud frequently quotes Baraitot (Tannaitic teachings not found in the Mishnah) from the Tosefta it only has one reference to a Tosefta and it is by no means certain that this is to our present Tosefta, which, scholars have suggested, is a post-Tannaitic compilation, although it undoubtedly is of Tannaitic origin.
Passages found in our Tosefta are often quoted in the Talmud in a paraphrased form for the purpose of the Talmudic discussion. The Tosefta is printed in sections in many editions of the Babylonian Talmud at the back of each tractate.
M. S. Zuckermandel published what is now the standard edition of the Tosefta (Pasewalk, 1880). Saul Lieberman has published an edition comprising three orders of the Tosefta, Zeraim, Moed, and Nashim (New York, 1955-73).
The study of the Tosefta was engaged in far less than that of the Mishnah and the Talmud, receiving only very few commentaries. But modern scholars have utilized the Tosefta to shed much light on the whole Talmudic period.