Iran and Saudi Arabia are rivals in the Persian Gulf and the Islamic world but there have been significant changes in their relationship over time with the two countries often caught between conflict and accommodation. What long term patterns in Iran’s policies towards Saudi Arabia can be identified to explain these shifts and what factors have shaped Tehran’s policies? Western observers have long been torn on this issue viewing Iran’s foreign policy as at times completely ideological, completely rational, or completely unpredictable. In this book James Devine argues that since 1987 the foreign policy of the Islamic Republic has been predominantly realist in nature, designed to ensure the security of the state rather than achieve ideological goals but that ideology has played an important part in determining who Iran views as enemies or friends. The amount of influence ideology and realism have played on Tehran’s foreign policy has varied depending on the level of regime consolidation and the intensity of factional competition, and so the interaction between realpolitik and ideology are carefully explored to identify long term patterns in Iran’s policies toward Saudi Arabia and clarify how they were formed.