Source criticism of the Torah in general, and the documentary hypothesis in particular, has been central to biblical studies for over a hundred years. The classical English introductions are Joseph E. Carpenter and George Harford, The Composition of the Hexateuch (London: Longmans, Green, 1902); Samuel R. Driver, Introduction to the Literature of the Old Testament, 9th ed. (Edinburgh: T & T Clark 1913), pp. 1–159; A.T. Chapman, An Introduction to the Pentateuch (Cambridge: Cambridge University Press, 1911). One of the first works to present a synopsis of the separate sources in English is William Edward Addis, The Documents of the Hexateuch (London: Nutt; New York: Putnam, 1893–1898). For recent introductions see Richard E. Friedman, Who Wrote the Bible? (Englewood Cliffs: Prentice-Hall, 1987), and Antony F. Campbell and Mark A. O’Brien, Sources of the Pentateuch (Minneapolis: Fortress Press, 1993), esp. chap. 1, pp. 1–20; see also Joseph Blenkinsopp, The Pentateuch, Anchor Bible Reference Library (New York: Doubleday, 1992). One recent critic of the source theory is Roger N. Whybray, The Making of the Pentateuch (Sheffield: JSOT Press, 1987).