This book is the first book-length analysis of investor accountability under general and customary international law, international human rights law, international environmental law, international humanitarian law, as well as international investment law. International investment law is currently facing growing criticisms for its failure to address corruption, abuse, environmental damage, and other forms of investor misconduct. Reform initiatives range from the rejection of international law as a governing regime for investors, to the dramatic overhaul of investment treaties that supposedly enable investor overprotection, to the creation of a multilateral international instrument that would enable the litigation of claims against errant businesses before an international tribunal. Whether these initiatives succeed in disciplining investors remains to be seen. What these initiatives undeniably show however, is that change is warranted to counteract this lopsided investors' international law. Each chapter in the book addresses a different and underexplored dimension of investor accountability, thus offering a novel and consolidated study of international law. The book will be of immense assistance to legal practitioners, academics and policy makers involved in the design, drafting, application and reform of various international instruments addressing investor accountability.