Part I. Where We Are in Macro and How We Got There: 1. Stories from the haunted vault: notes on a century of macroeconomics; 2. Post Walrasian macroeconomics: some historic links; 3. The DSGE model and the post Walrasian alternative in historical perspective; 4. Who is post Walrasian man?; Part II. Edging Away from the DSGE Model: 5. Social interactions and macroeconomics; 6. Macroeconomics and model uncertainty; 7. Restricted perceptions equilibria and learning in macroeconomics; 8. Not more so: some concepts outside the DSGE framework; Part III. Leaping Away from the DSGE Model: 9. Agent-based computational modeling and macroeconomics; 10. Multi-agent systems macro: a prospectus; 11. Agent-based financial markets: matching stylized facts with style; Part IV. Doing More Good than Harm: Roles of Business and Government in Critical Infrastructure Protection: 12. Characteristics of resilient systems and organizations; 13. Networks and interdependencies; 14. Public - private risk-sharing: the case of terrorism risk coverage; 15. Learning from experience: drawing correct analogies? Letting the data guide theory; 16. The past as the future: the Marshallian approach to post Walrasian macro; 17. Old world econometrics and New World theory; 18. Four entrenched notions post Walrasians should avoid; 19. Confronting the economic model with the data; 20. Extracting information from the data: a European view on empirical macro; Part V. Policy Implications: 21. Economic policy in the presence of coordination problems; 22. Monetary policy and the limitations of economic knowledge.