Since the 1990s, political transformations in Latin America, Eastern Europe, and Africa have contributed to progressive institutional reforms. Among those institutional changes, the adoption of gender quotas has been a worldwide phenomenon. In the 1990s, quotas “appeared in more than 50 countries” and have been introduced “by 40 more since 2000,” whereas they were rarely adopted during most of the twentieth century (Krook 2009:4). Gender quotas are institutional mechanisms that provide women with a means to secure legislative seats; they have been implemented in developed and developing countries and shaped by regional and international trends (Crocker 2007). Undoubtedly, research on gender quotas has become one of the fastest growing scholarships within the subfield of women and politics and deserves the attention of scholars and students of international relations and policymakers. However, most studies on gender quotas have focused on country-cases (Araujo 2003; Baldez 2004; Schmidt and Saunders 2004) or on several countries in a region (Htun and Jones 2002; Matland and Montgomery 2003; Araujo and Garcia Quesada 2006); others have dealt with the process of cross-national or subnational diffusion (Crocker 2007), but Krook's research goes beyond previous works. In her book, Krook takes on the various types of gender quotas, studies their origins and effects, and employs a pathbreaking framework of analysis to explain these trends. She develops an approach that outlines the range of actors, motivations, and contexts involved in quota reforms across the globe. Through a review of the existing quota literature, she identifies the factors that appear across many studies while acknowledging that there is no single model of quota adoption (p. 17) and that there are limits to prediction and prescription when it comes to the implementation of quotas (p. 224).