Cambridge has just published the "The New Cambridge History of Islam" in six volumes.
The Telegraph (6 February 2011) carries a review by Noel Malcolm which describes the new edition as:
"...a work of breathtaking scholarship that does justice to one of the world's great religions"
He goes on to write that:
"I have spent nearly a month reading these volumes, and have learned a huge amount – not least, from the final volume, about the background to the various forms of present-day “political Islam”. And I finish reading them impressed by two things: the way in which Islam itself has held together as a religion, stretched across multiple states and cultures with no Pope or hierarchical Church to maintain it; and the way in which this team of scholars has condensed so much learning, with such clarity, into a mere 4,929 pages."
You can read the full review here.