Monopolies or market power are usually considered to be an economic threat to markets and consumers. This book examines the theory, effectiveness and regulation of monopolies across the globe. The authors present topical research on monopolies, including the natural monopoly and third party access of the Swedish district heating market; the causes of market power; and, collusion and regulation in an electricity spot market and a study of the stability and efficiency of vertical collaboration networks from a microeconomic viewpoint.