The late Richard McKelvey was one of the great figures of American political science, a masterful theorist and analyst. Yet, until now, his foundational articles have never been collected in a single volume. ""Positive Changes in Political Science"" presents McKelvey's most influential work on voting and political behavior, accompanied by new essays from some of the most important figures in modern positive political theory. The book documents the incredible scope of McKelvey's work, and expands upon it with essays that set the agenda for future generations of research.