Most people show unconscious bias in their evaluations of social groups, in ways that may run counter to their conscious beliefs. This volume addresses key metaphysical and epistemological questions about implicit bias, including its effect on scientific research, gender stereotypes in philosophy, and the role of heuristics in biased reasoning. I hope to have shown just how relevant this book is for current discussions within social philosophy, epistemology, metaphysics, and moral psychology. Given the strong reliance on empirical literature, for example, providing alternative interpretations of existent empirical studies (as in Carole Lee's contribution), presenting empirical results themselves (as in Laura Di Bella, Eleanor Miles, and Jennifer Saul's contribution), the chapters in this book are not only interesting to philosophers but also to empirical researchers. Another strength of this book is the variety of questions it covers, ranging from a new understanding of stereotype threat (Ron Mallon's chapter) to expanding on the epistemic consequences of this phenomenon (Stacey Goguen's chapter); from the proposal that implicit biases are not mental states (Edouard Machery's chapter) to a prescription on how to pursue the ethical ideal of being unprejudiced without incurring epistemic costs (Alex Madva's chapter).