In his book Allah: A Christian Response Miroslav Volf argues that the faith of Christians and Muslims is directed toward the same divine referent. That is not to say that Christians and Muslims believe the same things about God. 
However, just as Christians and Jews assume they worship the same God, even though they disagree about key doctrines like the Trinity and the divinity of Jesus, Volf argues Christians and Muslims should admit that they worship the ‘same’ God despite their deep differences. Volf’s book is valuable for its nuance and logical rigor. It’s a fairly readable volume too. He make a careful and charitable case, while not falling into the silly “we all believe the same thing” nonsense.
Volf has recently written a timely piece on a related topic in the Washington Post. There he writes in defense of the suspended Wheaton College political science professor Larycia Hawkins. Hawkins was recently put on administrative leave for making a claim similar to Volf’s as part of her explanation for choosing to wear a hijab during Advent. Christianity Today summarizes that situation here. In the Post Volf argues convincingly that the college seems motivated by “anti-Muslim bigotry, not theology.”
