Activist hedge funds (AHFs), a relatively new alternative investment strategy, have had a large and growing impact on investing and on how public companies are managed. Although activist investing was once the province of corporate raiders, it is now an accepted hedge fund strategy. Often acquiring an influential stake in an undervalued public company before direct intervention, AHFs create their own catalyst for share appreciation. The actions or interventions taken by an AHF can range from direct communication with a board or management team to launching highly visible proxy fights or legal action. Through a review of academic and professional literature, this chapter offers a look into the relevant public policy discussion, implications for target companies in the short and long run, and the techniques AHFs commonly deploy.