Beyond Microfoundations discusses the foundations for a post-Walrasian macroeconomics and, in doing so, carries the work of Robert Clower and Axel Leijonhufvud to the present. This book spells out both why a new approach to macro is needed, and what the essence of the approach will be. This post-Walrasian approach to macro is neither Keynesian nor Classical, both of which have Walrasian foundations, but it offers an approach to macro in which Walrasian economics is turned on its head. Specifically, it rejects the Walrasian ad hoc assumptions of the existence of a unique equilibrium and of simple dynamics. That rejection leads one to a fundamentally different conception of macro than most macroeconomics have implicit in their formal model. Post-Walrasian macroeconomics offers a vision of macro in which micro foundations devoid of an explicit macro context have no place, but one in which institutions have a fundamental role. Post-Walrasian macroeconomics provides a foundation for a new macroeconomics for the 21st century built on the edges of chaos.