This document discusses monopolies and provides examples and analysis. It begins by defining key characteristics of monopolies, including that there is a single firm producing the entire supply of a product without competitors. It then analyzes how a monopolist determines the profit-maximizing level of output and price, finding where marginal revenue equals marginal cost and charging the highest price the market will bear. The document emphasizes that barriers to entry, such as legal harassment, patent protection, exclusive licensing, and bundled products, allow monopolies to exist and earn economic profits.