The Evolution of Modern States. Sweden, Japan, and the United States. By Sven Steinmo. Cambridge, UK: Cambridge University Press, 2010. 264 pp., $28.30 (ISBN 978-0-521-19670-3 (hb); 978-0-521-14546-6). Evolutionary theory currently occupies a somewhat marginal yet also discretely influential methodological position in the social sciences, and it often crosses the divides between sociology, political science, and even law. The book under review here, The Evolution of Modern States. Sweden, Japan, and the United States, utilizes evolutionary theory to assess the implications of the bundle of processes classified together as globalization for the welfare-state structures of advanced democracies, and it compares ways in which different institutional systems generate different (variably successfully) reactions to these processes. Globalization is construed as an aggregate of objective circumstances posing risks both for the domestic cohesion and the international competitiveness of particular societies (or particular political economies), exemplified here by Sweden, Japan, and the USA. The specific evolutionary dimension of this inquiry resides, first, in the fact that the book analyzes institutions in different societies as expressions of selective variation , which facilitate societal reactions to broader problematic constellations. Indeed, the book perceives “human agency” itself, defined as the volitional substrate of different institutions, as a complex aggregate of “intentional variation” (220), which makes it possible for a society incrementally to adapt to systemic pressures. Underlying this approach is a systemic-evolutionary sociology of political institutions. This approach accords a “structuring” role to institutions (xvii), which are defined as mechanisms for reproducing and consolidating variations that have obtained demonstrable adaptive success. Institutions are “systems of rules,” akin to biological rules governing cell behavior, and …