The Necessity of Organization describes Mary Kenney O'Sullivan's struggle to improve labor conditions through trade unionism. Appointed the first woman organizer for the American Federation of Labor in 1892, she went on to be a co-founder of the Women's Trade Union League, formed in 1903 as a cross-class alliance of women workers and their middle- and upper-class allies. The possibilities and limits of trade unionism for women, given the class and gender constraints of the period, are the focus of this book.