A year ago I read Guns, Germs and Steel by Jared Diamond and I enjoyed that book tremendously. Collapse was just as good.
The book describes how various societies have failed in the past, and analyses what the root causes of those failures were. Deforestation and unsustainable population growth were some of the common causes, as was an inability by some societies to changes cultural values when necessary. The Norse Greenlanders for example, seemed to have had a taboo against fish eating -- incredible if you consider the availability of fresh fish in Greenland.