1. Existence and Stability of the Cournot Oligopoly Solution (Or Equilibrium).- 1.1. No Product Differentiation.- 1.1.1. Existence Proof.- 1.1.2. Stability Analysis.- 1.2. Product Differentiation.- 1.3. Mathematical Appendix.- 1.3.1. A Theorem on Contraction Mapping.- 1.3.2. Global Stability of a Discrete System.- 2. Uniqueness of the Cournot Oligopoly Solution.- 3. Entry in the Cournot Model: Quasi-Competitiveness VS Perfect Competition.- 3.1. Introductory Remarks.- 3.2. Quasi-Competitiveness.- 3.3. Convergence to Perfect Competition.- 4. Revenue Maximizing Duopoly.- 4.1. Introduction.- 4.2. Stability Analysis.- 5. Stackelberg Duopoly Models Reconsidered.- 5.1. A Leader-Follower Model.- 5.2. Resolution of Stackelberg Disequilibrium in a Leader-Leader Model.- 5.2.1. Introductory Remarks.- 5.2.2. Local Stability.- 5.2.3. Global Stability.- 5.2.4. Unknown Market Demand Function and Global Stability.- 6. Extrapolative Expectations and Stability of Oligopoly Equilibrium.- 6.1. Introduction.- 6.2. Stability under No Product Differentiation.- 6.3. Product Differentiation and Stability.- 7. Adaptive Expectations and Stability of Oligopoly Equilibrium.- 7.1. No Product Differentiation.- 7.2. Product Differentiation.- 7.3. Mathematical Appendix.- 7.3.1. Some Theorems on Matrices with Quasi-Strictly Dominant Diagonal Blocks.- 7.3.2. Some Applications.- 8. Unknown Demand Function and Stability.- 8.1. Introduction.- 8.2. The Cournot Model with Unknown Market Demand Function.- 8.3. Adaptive Expectations and Unknown Demand Function.- 9. Probability Models.- 9.1. Probability Models with No Bayesian Learning.- 9.2. Bayesian Learning in Duopoly Models.- References.