From their website:
Established in Washington, D.C. over 50 years ago, the Center for Strategic and International Studies (CSIS) is a bipartisan, nonprofit policy research organization dedicated to providing strategic insights and policy solutions to help decision-makers chart a course toward a better world.
In late 2015, Thomas J. Pritzker was named Chairman of the CSIS Board of Trustees. Mr. Pritzker succeeded former U.S. Senator Sam Nunn (D-GA), who chaired the CSIS Board of Trustees from 1999 to 2015. CSIS is led by John J. Hamre, president and chief executive officer since April 2000.
Founded in 1962 by David M. Abshire and Admiral Arleigh Burke, CSIS is one of the world’s preeminent international policy institutions focused on defense and security; regional study; and transnational challenges ranging from energy and trade to global development and economic integration. For the past five years consecutively, CSIS has been named the world’s number one think tank for international security by the University of Pennsylvania’s “GoTo Think Tank Index.”
The Center’s 220 full-time staff and large network of affiliated scholars conduct research and analysis and develop policy initiatives that look to the future and anticipate change. CSIS is regularly called upon by Congress, the executive branch, and the media to explain the day’s events and offer bipartisan recommendations to improve U.S. strategy.