Its supply and demand, of course; "Freakonomics" established the market for popular economics paperbacks and this is one of several such books that have appeared recently. The pedagogic approach is very different from Levitt and Dubner's research-based original, though. Frank is an economics lecturer and despairs that students, even when they study economics, don't end up understanding much about it. Shockingly, surveys suggest maybe all those graphs and equations actually confuse ex-economics students. They often perform worse in answering everyday economically-related conundrums than the general populace! What this says about the competence of his teaching colleagues or the quality of the expensive undergraduate economics textbooks that pile up in university bookshops is left to the reader to decide.
Franks' approach is to ask his students to explain questions he puts to them (or they come up with) which represent little case studies of socioeconomic interaction. Why is there a light in your fridge not your freezer? Why do mobile phones cost less than their replacement batteries? Why do some bars offer free peanuts? Why are CD and DVD boxes different shapes? Why do women wear high heels? And so on. By pondering these, students should start to understand the basics of economics. All great fun and you genuinely end up beginning to "think like an economist", soon even challenging Frank's own sometimes simplified answers (...surely the aim of any pedagogic text). There is some theory underlying it but, as an ex-economics student myself, I thought a few graphs might actually have helped explain some concepts.
Nonetheless, cost-benefit analysis, opportunity cost, the tragedy of the commons, price-sensitivity, market segmentation and "behavioural economics" are some of the ideas entertainingly explained through example. The "economic naturalist" is therefore focused on fieldwork rather than abstract theory, but there is perhaps more to the title than that. Frank also draws, through for example the case of the elk's excessive antlers the link between evolutionary biology and economics and suggests that Darwinism was in part based on the ideas of Adam Smith's "Wealth of Nations".