The document discusses different market structures including perfect competition, monopoly, monopolistic competition, oligopoly, and cartels. It provides details on key features, pricing behaviors, and equilibrium conditions for each market structure. Perfect competition is defined by many buyers and sellers, homogenous products, and price being determined by supply and demand. A monopoly grants a single seller complete market control to set price. Monopolistic competition features product differentiation while allowing long run equilibrium with no profits. Oligopoly relies on interdependent actions among a small number of large firms. Cartels explicitly fix prices through collusive agreements.