Elizabeth Dilling - The Red Network: A "Who's Who" and Handbook of Radicalism for Patriots (1934)
A directory of early 30s political groups that's a fascinating time capsule of that era - though many of the attitudes and beliefs are just as prevalent now. I originally thought this was a guide for radicals and thought that was pretty nice (the Chicago location made sense) but started to read and it's actually an anti-communist guide against radicals, complete with attacks on Gandhi, Einstein, Jane Addams, pacifists and of course the New Deal.
The real basis of the book is the directory, listing a few hundred different groups with what appears to be solid information about them. Some of the conclusions, though, are a different story. It's no surprise to see the ACLU or IWW here but the American Association for Old Age Security? Apparently it has the "immediate objectives of the Socialist program". Harlem Progressive Youth Club? "Communist club". Finnish Cultural Federation? "Communist". Committees for Human Rights Against Naziism? Well, I don't quite follow their reasoning but it appears to be that while trying to save Jews in Germany the group isn't also protesting against Russia. NAACP? Communist infiltrated (and there's a direct slam against James Weldon Johnson). Bahai? Pacifists and the authors claim they aid communists.
Yep, the author was finding communists everywhere. The book ends with a directory of people, in case you want to look up names.