Contrary to widely held views of Ronald Reagan as a reflexive man of action, John Arquilla's sharply revisionist study argues that he was drawn to and driven by ideas. In Mr. Arquilla's view, Reagan during his presidency articulated important new concepts that fundamentally reshaped American foreign policy. He saw the effort simply to contain Soviet expansion as too defensive in nature, so he replaced it with a doctrine designed to help others free themselves from totalitarian rule. He objected to the notion of mutual nuclear deterrence on practical and ethical grounds, a stand that led him to negotiate arms reductions as well as explore the possibility of missile defense. On these issues, as Mr. Arquilla shows, Reagan overturned a long-standing consensus of public and expert opinion, helping achieve a favorable end to the cold war and the arms race that came with it. Yet there were also areas in which Reagan's policies played out less successfully-his inattention to the consequences of nuclear proliferation by smaller powers like Pakistan; his indecision in launching a preventive war against terrorism in the mid-1980s-with consequences that continue to haunt us today. In an incisive and balanced critique, Mr. Arquilla has set new standards of measurement for Reagan's foreign policy accomplishments and shortcomings. The Reagan Imprint is likely to be a source of lively debate within the establishment and outside it for years to come. With 15 explanatory graphs.