A professor friend of mine asks on his FB page:
Does anyone know of a good book on Old Testament theology or a Biblical Theology of the Old Testament? Something that is Christian yet does not have as its starting point interpreting the OT through a Christian lens.
my guess is he was an NT focus in his PhD work – this will be for a Bachelor level class.
offer him some suggestions through the comments here. thanks!
συνεσταύρωμαι: living the crucified life 
Well Walter Brueggemann’s OT Theology takes the message of the OT seriously “on it’s own,” but even he examines it at many points “through a Christian lens.” It seems difficult to me to do “Christian” OT work but not examine it “through a Christian lens.”
I would agree with adhunt. Reading Walter Bruuggemann is the best way to go – way on earth you would want to go that way, I really don’t know.
Joel, he wants to avoid theologies that first defines the “center” and then scans the OT for how it plays out or supports the “center,” etc . He wants to let the texts tell him their themes. If that makes sense.
Dr. Aker used Graeme Goldsworthy’s “Preaching the Whole Bible as Christian Scripture: The Application of BT to Expository Preaching.” I trust Dr. Aker’s judgment. There was a minor disagreement he had with Goldsworthy (it’s been a while and I don’t remember exactly, so I’ll refrain from guessing). Definitely worth a serious consideration from your friend.
Brueggemann’s OT theology is a good one but it’s a little dense for bachelor’s level. I would try something like this theological “intro” that pulls from writer’s like Brueggemenn and Fretheim. The other authors seem to balance Brueggemann towards a more themes “outward” approach.
Robin Routledge has one from IVP. I read it through last year and liked it fairly well.
I used New Testament Theology by G.B. Caird (Oxford, 1994). It’s old but a classic for NT theology.