Throughout the 20th century, women were leading intellectuals on International Relations (IR). They thought, wrote, and taught on this subject in numerous political, professional, intimate, and intellectual contexts. They wrote some of the earliest and most powerful theoretical statements of what would later become core approaches to contemporary international theory. Yet, historical women, those working before the late 20th century, are almost completely missing in IR's intellectual and disciplinary histories, including histories of its main theoretical traditions. In this forum, leading historians and theorists of IR respond to the recent findings of the Leverhulme project on Women and the History of International Thought (WHIT), particularly its first two book-length publications on the centrality of women to early IR discourses and subsequent erasure from its history and conceptualization. The forum is introduced by members of the WHIT project. Collectively, the essays suggest the implications of the erasure and recovery of women's international thought are significant and wide-ranging.