In the midst of globalization, technological change and economic anxiety, we have deep doubts about how well that task of investor protection is being performed. In the U.S., the focus is on the Securities & Exchange Commission. Part of the explanation is economic and political: the failure to know the right balance between investor protection and capital formation, and the resulting battle among interest groups over their preferred solutions. This book's main claim, however, is that regulation is also frustrated at nearly every turn by human nature, as exhibited both on the buy-side (investors) and sell-side (corporate executives, bankers, stockbrokers). There is plenty of savvy and guile, but also ample hope, fear, ego, overconfidence, social contagion and the like that persistently filter and distort the messages regulators try to send. This book is the first sustained effort to link the key initiatives of securities regulation with our burgeoning awareness in the social sciences of how people and organizations really behave in economic settings. It examines why corporate fraud occurs and how best to deter it and compensate its victims; the search for an edge via insider trading; the disclosure apparatus and its gatekeepers; sales efforts and manipulation in Ponzi schemes, internet scams, private offerings and crowdfunding; and how this all helps explain the recent global financial crisis. It ends by turning these insights back on the task of regulation itself, and the strategies (and frustrations) of making regulation work in a financial world that is at once increasingly sophisticated yet deeply human and incurably flawed.