Preface 1. From Keynesian to New Keynesian economics. 2. Keynesian microfoundations in historical perspectives. Part I Real Rigidities 3. The labour market and real wage rigiditry. 4. Credit rationing and imperfect capital markets. 5. Real rigidities in the goods market. Part II Nominal Rigidities Introduction 6. Rational models of irrational behaviour. 7. Price setting with adjustment cost. 8. Real and nominal price rigidity: further issues. Part III Coordination Failures and Hysteresis 9. Coordination failures 10. Hysteresis Conclusions.