1. The Need for a Nonlinear Theory of Economic Dynamics.- 1.1 Introduction.- 1.2 Early Nonlinear Theories.- 1.3 Development of the Theory of Dynamical Systems.- 1.4 Problems in the Current State of Economic Dynamics.- 2. The Theory of Dynamical Systems.- 2.1 Introduction.- 2.2 Existence and Uniqueness Results.- 2.3 The Linear System x - Ax.- 2.4 Nonlinear Systems on the Plane.- 2.5 Analysis of Limit Cycles.- 2.6 Relaxation Oscillations.- 2.7 Higher Dimensional Nonlinear Systems.- Appendix 2.1.- 3. A New Look at Some old Endogenous Cycle Theories.- 3.1 Introduction.- 3.2 A General Model of Multiplier- Accelerator Interactions.- 3.3 Goodwin's Nonlinear Accelerator Model.- 3.4 A Saturation Type Nonlinear Accelerator.- Appendix 3.1.- Appendix 3.2.- 4. Analysis of the Effects of Time Lags and Nonlinearities in Macroeconomic Models Incorporating the Government Budget Restraint.- 4.1 Introduction.- 4.2 Specification of the Model.- 4.3 Dynamic Behaviour of the Model.- Appendix 4.1.- Appendix 4.2.- 5. Limit Cycles in Higher Dimensions - the Effect of Time Lags on Goodwin's Model of Cyclical Growth.- 5.1 Introduction.- 5.2 The Goodwin Model with a Time-Lag.- 5.3 Local Stability Analysis.- 5.4 Approximation of the Limit Cycle.- 5.5 Discussion.- Appendix 5.1.- Appendix 5.2.- Appendix 5.3.- Appendix 5.4.- Appendix 5.5.- Appendix 5.6.- Appendix 5.7.- 6. The Cobweb Model: Its Instability and the Onset of Chaos.- 6.1 Introduction.- 6.2 The Nonlinear Cobweb Model.- 6.3 Discrete Time Dynamics.- 6.4 Period Doubling to Chaos.- 6.5 Onset of Chaos in the Cobweb Model.- 6.6 Discussion.- 7. Perfect Foresight Models and the Dynamic Instability Problem From a Higher Viewpoint.- 7.1 Introduction.- 7.2 The Basic Nonlinear Model of Monetary Dynamics.- 7.3 The Naive Dynamics of the Perfect Foresight Case; ? = 0.- 7.4 The Dynamics of the Adaptive Expectations Case; ? > 0.- 7.5 Adaptive Expectations as ??0+.- 7.6 The Discrete Time Model of Monetary Dynamics.- 7.7 Discussion.- Appendix 7.1.- Appendix 7.2.- Appendix 7.3.- Appendix 7.4.- Appendix 7.5.- Appendix 7.6.- 8. Conclusions and Further Developments.- References.