The year 2000 was the first time the U.S. Census permitted respondents to choose more than one race. With this shift, the start of the millennium coincided with the official rise of the "multiracial population." Although the U.S. has long recognized that a "mixed-race" population exists, the contemporary multiracial population presents different questions and implications for today's diverse society. This book is the first to bring a systematic critical race lens to the scholarship on mixedness. Avoiding the common pitfall of conflating "mixed" with "multiracial," the book not only carefully separates the two but also reveals how identity forms and fluctuates such that people with mixed heritage may identify as mixed, monoracial, and/or multiracial throughout their lives. It analyzes the dynamic and variegated manifestations of mixedness, including at the global level, to reveal its complex impact on both the structural and individual levels, critically examining topics such as family dynamics and racial socialization, multiraciality in media and popular culture, and intersections of race, gender, class, and sexual orientation. Integrating diverse theories, qualitative research, and national level data, this accessible and engaging book is essential for students of race and those looking to understand the new field of multiraciality.