6 ½ X 9 7/16 in Chapter 1. Recent Developments in the Theory of Regulation (Mark Armstr ong and David Sappington) This chapter can be viewed as a s uccessor to the chapter by David Baron in the original HIO, and to a les ser extent those by Ronald Braeutigam and by Roger Noll. Relative to th e Baron chapter, this chapter focuses more on practical regulatory polic ies and on multi-firm regulation.

Chapter 2. The Economic Analysis of Advertising (Kyle Bagwell) This c hapter discusses advertising, which received a brief treatment only in p assing in the first two HIO volumes. More generally, this c hapter fills a larger gap, as we know of no thorough modern survey of th is large literature.

Chapter 3. Empirical Mo dels of Entry and Market Structure (Steven Berry and Peter Reiss) This chapter describes empirical models of entry and exit that in fer aspects of firms competitive environment from the number of competi tors in a market. The focus is on within industry comparisons, say for e xample on differences across separate geographical markets for the same