Investigate the Mutual Learning among Civilizations, of Which there is More Historical Evidence than there is for the Clash of Civilizations
I'm not surprised to hear that his approach has many critics within the discipline. It is grounded in a positivist approach where things can actually be studied as reality, rather than simply taking a posture of critique towards dominant approaches. The genuine (if measured) optimism I'm sure strikes a false note for some people but I found it refreshing.