What is energy security? On April 12–13, the Council on Foreign Relations convened academics, policymakers, and industry experts to assess the security implications of the way the world produces and consumes oil and natural gas. The workshop aimed to explore important issues at the intersection of oil, gas, and national security, and identify areas for future research. The first day focused on assessing the state of knowledge on energy and security, while the second explored U.S. policy options going forward. This summary report presents a broad agenda for energy security research that emerged from the meeting.