In an era when old alliances are under severe pressure and major powers--the Soviet Union and the United States--are discovering that their protective umbrellas no longer provide an irresistible attraction for middle and small size states, the entire question of the theory and function of partial security arrangements deserves a serious investigation. Although some inquiry into the power displaced by small states has taken place (notably Annette Daker Fox's The Power of Small States), relatively little has been done to establish the role of mini-nations in the operation of the balance of power during the period when it was in its ascendancy. Professor Rothstein, a young scholar of considerable reputation, has performed a fine service in closely examining the policy performance of small states--largely European--in the years 1815 to 1939. He concludes that their behavior is of an order different from that of simply ""Great Powers writ small."" His analysis of the complex international relations of the period convincingly maintains that the attraction index of great powers to small powers is based on more variegated factors than the latter's military potential.