In this work, the author works towards a theory of influence in international politics that recognizes the power of promises and assurances as tools of statecraft. He offers an analytic treatment, drawing on international relations theory, deterrence theory and cognitive and social psychology. Building on prospect theory (from cognitive psychology), he develops a testable theory of influence that suggests promises are most effective when potential aggressors are motivated by a desire to avoid loss. Davis then considers a series of case studies drawn principally from German diplomatic relations in the later 19th century and early 20th century. From the case studies - which focus on such issues as European stability, colonial competition and the outbreak of World War I - Davis shows how a blending of threats and promises according to reasoned principles can lead to a new system of more creative statecraft.