In his book Allah: A Christian Response, Miroslav Volf argues that the God of the Quran and the God of the Old and New Testaments can be fairly understood as the same being. He argues this by demonstrating that, while there are differences in emphasis, the Quran and the Christian scriptures ascribe the same character to God. Further, all the things that Islam rejects about the trinity are also rejected by orthodox Christian formulations of the trinity.
What do you think? Are the God of the Christian scriptures and the God of the Quran the same? What would it mean for Christian/Muslim relations to say that they are? Or to say that they are not?