The think thanks you find on each tab likely cover a range of policy realms, but they've been sorted based on their notable coverage in one or more specific domains.
Each think tank's name will include the country where its headquarters are located, but almost all these organizations cover international issues.
Below, you'll find a short list of think tanks known for their interdisciplinarity, making them good starting points for general research.
If you want to browse a larger selection of non-US think tanks, the Harvard Kennedy School has an extensive list broken out into regions.