Scholars have spilled a remarkable amount of ink on the topic of takeover defenses. Despite – or perhaps because of – this, there remains remarkably little scholarly consensus on the topic. This chapter provides an overview of some of the ongoing scholarly debates surrounding corporate takeover defenses. It begins with background on the poison pill, widely considered to be the most important takeover defense for U.S. firms, before turning to studies of poison pills and other takeover defenses, in particular staggered boards. The chapter then considers the scholarly literature on why different firms adopt different levels of takeover defenses. The final two sections of this chapter discuss rapidly growing areas of scholarship that have implications for the literature on takeover defenses: the debate over whether U.S public corporations are myopic and the scholarship surrounding empty voting.