Accodring to Wikipedia, “The oldest known source, but questionable explanation for the expression “baker’s dozen” dates to the 13th century in one of the earliest English statutes, instituted during the reign of Henry III (1216–1272), called the Assize of Bread and Ale. Bakers who were found to have shortchanged customers could be subject to severe punishment. To guard against the punishment of losing a hand to an axe, a baker would give 13 for the price of 12, to be certain of not being known as a cheat. Specifically, the practice of baking 13 items for an intended dozen was insurance against “short measure”, on the basis that one of the 13 could be lost, eaten, burnt, or ruined in some way, leaving the baker with the original legal dozen.”
Lest I be accused of missing any significant work, here is a list on my top thirteen modern OT Theologies:
13.Jacob, Edmund. Theology of the Old Testament. New York: Harper & Brothers Publishers, 1958.
12.Brueggemann, Walter. Old Testament Theology: An Introduction. The Library of Biblical Theology. Nashville: Abingdon Press, 2008.
11.Clements, Ronald E. Old Testament Theology: A Fresh Approach. Marshalls Theological Library. London: Marshall, Morgan and Scott, 1978.
10.Vriezen, TH. C. An Outline of Old Testament Theology. Newton, MA: Charles T. Branford Company, 1960.
9.Zimmerli, Walther. Old Testament Theology in Outline. Atlanta: John Knox Press, 1978.
8.Gerstenberger, Erhard S. Theologies in the Old Testament. Minneapolis: Fortress Press, 2002.
5.Waltke, Bruce. An Old Testament Theology: An Exegetical, Canonical, and Thematic Approach. Zondervan, 2007.
6.Rendtorff, Rolf. The Canonical Hebrew Bible: A Theology of the Old Testament. Leiden: Deo Publishing, 2005.
5.Terrien, Samuel. The Elusive Presence: Toward a New Biblical Theology. San Francisco: Harper & Row Publishers, 1978.
4.Eichrodt, Walter. Theology of the Old Testament. 2 vols. Westminster John Knox Press, 1967.
3.von Rad, Gerhard. Old Testament Theology, 2 vols. Westminster John Knox Press , 2001.
2.Goldingay, John. Old Testament Theology, 3 vols. IVP Academic, 2003-2009.
1.Childs, Brevard. Biblical Theology of the Old and New Testaments: Theological Reflection on the Christian Bible. Augsburg Fortress Publishers, 1993.
I know, that this list will not satisfy all. So if you are tempted to grab your theological axe…What would you would add? Any of these you would remove? Why?
OLD TESTAMENT THEOLOGY: ITS HISTORY AND DEVELOPMENT, by John H. Hayes & Frederick Prussner. Louisville: Westminster John Knox Press, 1984. Pp. 290. $29.95 (paper).
This is Prussner’s PhD dissertation edited and updated by John Hayes. On pages 233-239 it gives another helpful intro into von Rad for those that are new to this Old Testament giant.
First, the key to understanding von Rad’s work is found in his choice of the subject matter. According to him the OT theologian is mainly concerned with “Israel’s own explicit assertion about Yahweh.” 
Second, H&P outline six basic principles that underlie von Rad’s approach to the OT:
a.OT itself must set the agenda for writing a theology.
b.OT is primarily a book of history concerned with the divine acts in history.
c.Traditions about Israel’s sacred history were formulated as testimonies and credal confessions which were products of Israel’s thinking about itself.
d.OT does not contain a single, unified theology.
f.Linkage of promise and fulfillment is crucial to von Rad’s understanding of how older traditions functioned in the life of Israel.
g.Since the basic content of OT is the sacred story, “retelling remains the most legitamate form of theological discourse on the OT” [vol.1, 121]
Third, H&P level few criticisms against von Rad’s work that I could try to summarize under three main headings:
They point out inconsistencies in von Rad’s work. These have to do with his inability to completely avoid systematic theological discussion which he criticizes Eichrodt for and his failure to really carry out the mode of “retelling”. H&P site an example of von Rad’s position on Deuteronomy as a product of 7th century BC which goes against the ancients’ affirmation of its Mosaic origin.
Furthermore, von Rad is accused of Theological Romanticism by overemphasizing the significance of Israel’s historical traditions at the expense of the prophets’ personhood and individuality in thought and experience.
Finally, H&P chide von Rad for using the form of Heilgeschichte [salvation history] but without the insistence on factual historicity that usually accompanies it.
OLD TESTAMENT THEOLOGY, vols. 1 and 2, by Gerhard von Rad, with an introduction by Walter Brueggemann. Louisville: Westminster John Knox, 2001. Pp. 502; 496. $29.95 each (paper).
Walter Brueggemann has furnished a good introductory article for those of us not familiar with von Rad’s work yet.
First, Brueggemann provides an insightful background to von Rad’s life that explains the roots of his project. As a young pastor, von Rad was “formed and shaped by the force, vitality, and liveliness of the work of Barth” (xi).
Second, Brueggemann identifies three features of von Rad’s work that reflect Barth’s influence:
(1) the primal mode of theological statement is narrative. The Credal statements of Deuteronomy 6:20-24, 26:5-6, and Joshua 24:1-13 are at the heart of the Old Testament.
(2) this narrative is testimony, that is, “active, out-loud, public utterance whereby Israel makes its faith claim in an either/or mode of presentation that vigorously counters other religious claims” (xv)
(3) this testimony that is central to the Old Testament is a counter-truth against the claims of “Canaanite religion.” (xiii).
Third, Brueggemann’s main and by and large only criticism of von Rad reflects his own academic seinsitivity. He decries the fact that von Rad “did not acknowledge the existence of vibrant contemporary Jewish faith communities” (xxvi).