In Intersectionality, philosopher Naomi Zack presents a novel philosophical account of intersectionality - the process by which people already oppressed, experience more oppression because of their intersecting identities. Examples include women who experience racism or poor people who are under-served. Identifying such intersections allows for more precise analysis of oppression, as well as newly recognized identities, such as blackwomen or homeless people of colour. Zack here explores the meaning of intersectionality through analysis of current events and controversies including the #MeToo movement, the COVID-19 pandemic, and class opportunities for minorities in higher education. Her analysis develops a robust definition of intersectionality in terms of inclusion, recognition, and diversity; works out ontological issues about the relationship between persons, labels, and identity; explores the distinction between abstract philosophical thinking and activism; and discusses how intersectionality can be an effective basis for empowerment, as well as understanding. Zack's distinctively philosophical account explains how intersectionality, considered as a method of analysis, works and can be employed in many areas of progressive thought across varying disciplines. She concludes that identifying and challenging the injustice of oppressions logically requires a broad humanistic framework, that intersectionality cannot be reduced to mere talk of diversity and inclusion, and that intersectionality itself is a progressive method of analysis worthy of philosophical attention.