This thesis consists of four essays in economics related to the pharmaceutical market. The first essay, Pharmaceutical Pricing in a Regulated Market, compares the pricing of new pharmaceuticals in the Swedish market where prices are regulated, with the results of Lu and Comanor who studied the pricing of new pharmaceuticals in the US market. The results indicate that price regulation discourages the use of penetration strategies and decreases price competition between brand name drugs. The second essay, Innovativeness and Market Shares in the Pharmaceutical Industry, analyzes the pharmaceutical market in a model of horizontal and vertical product differentiation. The implications from the model are tested on data from the Swedish pharmaceutical market. Vertically differentiated drugs are found to gain larger market shares, command higher prices, and be less sensitive to substitutes than drugs that are only horizontally differentiated. The third essay, Generic entry before and after reference prices, examines the effect of the reference pricing system on generic entry in markets where brand name pharmaceuticals lose patent protection. The main result is that savings due to increased competition in markets affected by the reference pricing system may have been outbalanced by higher prices due to less competition in markets where the reference pricing system led to deterred entry. The fourth essay, Innovative Drugs and the Increase in Pharmaceutical Expenditures, seeks to establish the most important factors behind the growth in pharmaceutical expenditures. One important conjecture is that the change in the drug price index has little impact on the rate at which pharmaceutical expenditures grow. Instead, the introduction of new innovative drugs seems to be the most important driving force of the growth in pharmaceutical expenditures. / Diss. (sammanfattning) Stockholm : Handelshögsk., 2001