International arbitration is a remarkably resilient institution, but many unresolved and largely unacknowledged ethical quandaries lurk below the surface. Globalization of commercial trade has increased the number and diversity of parties, counsel, experts, and arbitrators, which have in turn, led to more frequent ethical conflicts just as procedures have become more formal and transparent. The predictable result is that ethical transgressions are increasingly evident and less tolerable. Despite these developments, regulation of various actors in the system — arbitrators, lawyers, experts, third-party funders, and arbitral institutions — remains ambiguous and often ineffectual. This book systematically analyses the causes and effects of these developments as they relate to the professional conduct of arbitrators, counsel, experts, and third-party funders in international commercial and investment arbitration. This work proposes a model for effective ethical self-regulation, meaning regulation of professional conduct at an international level and within existing arbitral procedures and structures. The work draws on historical developments and current trends to propose analytical frameworks for addressing existing problems and reifying the legitimacy of international arbitration into the future.