This book is a collection of previously published essays. It makes sense as a collection because these essays have more to say together than the sum of each individually. That collective message is largely methodological. It concerns the possibility of a style of economic theory rather different from the current stock in most economic journals.

What mainly differentiates these articles from most economic theory today is their willingness to entertain the consequences of new assumptions. Most of the best economic theory of the last forty years has concerned the consequences of application of supply and demand theory to new areas (such as resource economics, the demand and supply of patents, the economics of discrimination, and the economics of foreign exchange markets) and also to the solution of classical problems (such as proof of the existence of equilibrium and the Pareto optimality of that equilibrium in a classical Walrasian model).

In contrast, these essays represent an alternative approach to the advance of economic theory. That alternative approach is to explore the consequences of new behavioral assumptions. To give one example of this exploration, prior to the publication of “The Market for ‘Lemons’” there was very little work on the economic consequences of imperfect information (except in formal game theory). This omission is curious because information imperfections are consistent with economists' utilitarian view of the world.