Book excerpt: In this concise, provocative, and trenchant book, Alexander J. Motyl argues that social scientists must pay more rigorous attention to the formulation of concepts, as they provide the basis for clear thinking, good research, and intelligent formulation of theories. Before even contemplating the question of whether or not theories "fit the facts" and explain what they purport to explain, it behooves us to ask whether or not theories make sense conceptually. Focusing his "conceptual explorations" on three phenomena -- revolutions, nations and nationalism, and empires -- Motyl challenges the sloppy thinking that so often surrounds these three interrelated concepts, and moves our understanding of them -- and their implications for both theory and practice -- toward greater precision.