One joy of studying history is discovering people living meaningful lives and behaving in unusual ways that are startling to the modern reader--young or old. Why did pre-modern people living hundreds or even thousands of years ago do things so differently than we do? Robert Whaples states that Economic historians conclude that the key difference between us and them is that we collectively know a lot more than they did. Mankind's knowledge base has expanded dramatically over time (especially since the advent of the scientific revolution); these improvements in technology are our key advantage. The blessings of advancing technology and supportive institutions (such as secure property rights and competitive markets) have allowed the standards of living of modern populations to reach heights unimaginable to our distant ancestors. Whaples continues with a comparison of pre-modern and modern trade advantages and differences, and the effect that the Malthusian trap plays in economic history.