Diplomacy for the 21st Century recommends steps that the department should embrace in order to take full advantage of the leading science and technology (S&T) capabilities of the United States. These capabilities provide the department with many opportunities to promote a variety of the interests of the United States and its allies in a rapidly changing world wherein S&T are important drivers of economic development at home and abroad and help ensure international security. This summary version highlights the main ideas and key messages of the full report.