This is a treatment of the effects of increased transparency on financial markets: an important and highly controversial issue for both traders and regulators. Focusing on three main themes - market transparency, the consolidation-fragmentation of trading systems and the scope of regulation (i.e. which markets, and which traders within those markets, should be subject to regulation) - the book highlights the importance of these issues to all markets throughout the world. The book draws on research from eight UK-based investment exchanges, Deutsche Borse in Frankfurt and documentary evidence from the US markets and their regulators, enabling the identification and documentation of the current situation and consideration of what fresh regulatory approaches are required for this new and fast evolving situation.