In 2015, shortly after Caitlyn Jenner came out as transgender, Rachel Dolezal — president of a local NAACP chapter — was “outed” as white by her parents, sparking a media debate about the fluidity of gender and race. If Jenner could legitimately identify as a woman, could Dolezal not likewise identify as black? Although sex, unlike race, has a biological grounding, the choice or change of sex or gender paradoxically meets with greater acceptance than the choice or change of race. Looking at race and ethnicity through the lens of the transgender experience — not only as movement from one category to another, but also as a position between and beyond existing categories — Rogers Brubaker underscores the malleability, contingency and arbitrariness of racial categories. Starting from the controversial coupling of “transgender” and “transracial,” he shows how gender and race, long understood as stable, innate and unambiguous, have in recent decades come to be seen as mutable and open to choice.