I'm not really going to review this...there is too much to review except to say if you find yourself with just a few hours in Montreal, this is probably the place to spend them. Check the other reviews for things to do.
I found the Montreal city website dedicated to a walking tour of Old Montreal incredibly helpful for learning the history of the area one building at a time. http://www.vieux.montreal.qc.ca/tour/eng/0cartea.htm. (With Pictures!)