Historically, specialists and other floor brokers, in direct contact on the trading floor, have been at the heart of operations at the national U.S. equity exchanges. At the other end of the spectrum, electronic trading platforms have characterized most other equity markets globally for many years. Recent developments at the NYSE have moved in this direction, but fundamental questions effecting market quality remain. Can the unique services offered by the floor be provided as effectively in an electronic environment? Which environment would institutional and retail traders each find most suitable to their special needs? Which environment offers better price and quantity discovery? These are some of the questions that are addressed in this book, while providing perspective on the future direction that exchange market structure is likely to follow in the coming years.