This is the second book by Jared Diamond I read, after "Guns germs and steel". Diamond is an encyclopedia of scientific knowledge - his books are a delightful mixture of history, archeology, zoology, anthropology and other sciences. "Collapse" deals with the question of why some historic societies have failed (Easter Island, the Maya Empire, Greenland Norse and others) versus other societies that have suceeded (Japan, Iceland, ...). He defines a "five point framework" upon which he judges the progress of societies: impact on environment, climate changes, hostile neighbours, friendly neighbours and the society's response to its problems. All these points are carefully discussed and presented for numerous past societies. One of the things I like most about this book is the exciting account of results obtained by various means to study the past. Archeology, carbon dating, study of plant pollen, study of tree rings, and general logical inferences are all very interesting to read about. Diamond also spends a lot of time discussing agriculture, and in fact parts of the book certainly fits the criteria for "Popular agricultural engineering". The latter parts of the book proceed discussing some modern societies (like Rwanda, China and Australia), presenting the problems these societies are having and comparing them with past societies. It is a very interesting read and the conclusions are enlightening, albeit somewhat gloomy. I think I learned a lot from the book. I will no longer consider human history as a roughly linear progress of societies and people that have transformed through the ages. History of societies is more like a multi-dimensional stock market, with certain societies indeed suceeding and transforming in the future, but other societies that utterly fail and exterminate themselves, although being quite prosperous and powerful. It is an important lesson to learn for the world we live in today. All in all, this book is highly recommended.