The hostage takers are either small terrorist teams or large groups of militants, often led by armed elements. Diplomatic facilities have been seized in at least 27 countries including El Salvador, Iran, and the United States. Embassies of Egypt and the United States have been favorite targets. In 20 out of 36 cases where demands were made, the attackers directed their demands to the host country: in 10 other cases, the demands were directed to the government whose embassy had been seized. In the six remaining cases, terrorists made demands on both governments or on other governments. The rate of success achieved by the hostage takers has declined with time, indicating that governments have become more resistant to terrorists holding hostages. Terrorist demands were fully met in less than 17 percent of the cases, and terrorists were arrested, captured, or killed in 48 percent of the cases where they made demands. One-third of the terrorists who took part in embassy seizures were killed or captured, although the remainder escaped punishment. Most of the hostages (98 percent) were released (or rescued) unharmed. Security appears to work in that the embassies of Nations that have been most frequently targeted by terrorists in other kinds of incidents (United States, United Kingdom, Israel, West Germany, and France), are underrepresented in takeover attempts. The report concludes that governments can be expected to remain resistant to meeting terrorist demands. Thus, longer sieges can be expected. In addition, there is a greater likelihood that these sieges will be ended by force. Figures and tabular data are given. An appendix contains a chronology of embassy takeovers, 1971-80. (Author abstract modified)