Few economists can accurately account for the distinctions between microeconomics and macroeconomics or properly describe their relationship to each other. Scholars attempting to bridge the gap between the two subdisciplines have turned to analyzing the microfoundations of macroeconomics. However, much of this microfoundations literature has depicted microeconomics as concerned only with individual behavior and has regarded macroeconomic propositions as consequences of the interaction of rational individuals.

In Microfoundations, Maarten Janssen aruges that the concern in microeconomics with the functioning of markets is the real underpinning for microfoundations theories. Using simple examples to illustrate his arguments, Janssen analyzes the aggregation problem, the individualistic foundations of equilibrium theories and the rational expectations hypothesis. His book combines a thorough treatment of the technical aspects of these subjects with a critical discussion of the deeper philosophical issues at stake.