Traister highlights how single women have historically been at the forefront of major social movements. From the temperance movement to the fight for abolition and women's suffrage, unmarried women have often been the driving force behind significant societal changes. Their independence allowed them to challenge the status quo and advocate for reforms that benefited all of society.

The book examines the shifting patterns of marriage in the United States, noting that fewer women are marrying at a young age. This demographic shift has profound implications for society, as it reflects changing attitudes towards marriage, career, and personal fulfillment. Traister explores how this trend is reshaping the social and economic landscape.

Traister's work emphasizes the diversity among single women, considering factors such as race, class, and sexual orientation. By including a wide range of voices and experiences, the book provides a nuanced understanding of what it means to be an unmarried woman in America today. This inclusivity enriches the narrative and underscores the varied ways in which single women navigate their lives and contribute to society.