This is an advanced theoretical treatment of pricediscrimination in imperfectly competitive markets. Weaddress issues such as the viability of pricediscrimination when markets are oligopolistic ratherthan monopolistic. In particular, it seeks todetermine what effects the introduction ofcompetition to a monopoly market will have on afirm's ability to price discriminate. Also examinedis price discrimination in the presence of collusionamong consumers, as well as the connection between amonopolist's linear pricing and resale among consumers.