Book excerpt: To understand American politics and government, we need to recognize not only that members of Congress are agents of societal interests and preferences but also that they act with a certain degree of autonomy and consequence in the country’s public sphere. In this illuminating book, a distinguished political scientist examines actions performed by members of Congress throughout American history, assessing their patterns and importance and their role in the American system of separation of powers. David R. Mayhew examines standard history books on the United States and identifies more than two thousand actions by individual members of the House and Senate that are significant enough to be mentioned. Mayhew offers insights into a wide range of matters, from the nature of congressional opposition to presidents and the surprising frequency of foreign policy actions to the timing of notable activity within congressional careers (and the way that congressional term limits might affect these performances). His book sheds new light on the contributions to U.S. history made by members of Congress.