The Congressional Research Service does excellent Congressional Research Service reports on a variety of subjects for the U.S. Congress. They have been difficult to access for most U.S. citizens Currently, a few sites provide selected unclassified reports. You can find some at EveryCRSReport.com. Another source is the Federation of American Scientists.
Now The American Library Association (ALA) announces that victory in a 20 year battle to make these reports available may be close From the announcement: “Political insiders know that these reports, produced by the nonpartisan expert staff at CRS, are excellent sources of information about nearly every conceivable public policy topic. But CRS reports have not been routinely published, and so they have only been accessible to those with a connection on Capitol Hill or through an unofficial third-party source.”