Keen first compares neoclassical approaches to modelling with heterodox ones. Then he discusses in length the required assumptions and the inconsistencies of the aggregate demand and supply model, which is extrapolated from a micro perspective. At the end some dynamic models with feedback mechanisms are shown.

Firms are the primary places where economic activity takes place in modern capitalist economies: they are where most stuff is produced; where many of us spend 40 hours a week; and where big decisions are made about how to allocate resources. Establishing how they work is hugely important because it helps us to understand patterns of production and consumption, including how firms will react to changes in economic conditions and policy. And a well-established literature – led by post-Keynesians and institutionalists – holds that the best way to determine how firms work is to…wait for it...ask firms how they work. This a clearly sensible proposition that is contested in economics for some reason, but we’ll ignore the controversy here and just explore the theory that springs from this approach.

Designed to give second-year undergraduates an intuitive understanding of basic mathematical techniques, and when and why they are applicable. Building on the traditional framework of calculus, the notion of a concave function is used to link the new algebraic methods with the more familiar graphical approachoand to introduce the modern use of duality in economic analysis.