Using novel leadership data from eleven developed parliamentary democracies between 1980 and 2020, this Element asks how gender conditions party leaders' candidacy, selection, and survival. It examines the life cycle of party leadership careers of 276 leaders with a focus on three categories of variables: performance indicators, (s)election details, and inclusiveness of political culture. It tests the existing theories of glass ceilings and glass cliffs on how certain conditions make it more likely that women run for and are selected as party leaders. The Element also offers an original quicksand theory on leaders' survival in office that, for women, leadership is akin to being caught in quicksand. Several factors agitate the quicksand and make them sink faster. The authors data shows support for the glass ceiling and quicksand theories. Yet, they find mixed support for the glass-cliff theory. The Element offers unique insights into women's experience with party leadership.