I've been reading the Cambridge Companion to Logical Empiricism, and finding quite a lot of interest. It is generally material I was vaguely aware of, having been interested in this area for some time, but there's a lot of detailed evidence which I'm very glad to now have available. Thus, for example, I had long thought that the general lack of awareness in the United States of the rather far left political leanings of the Logical Positivists was probably partly a result of their tending not to emphasize such leanings during the early years of the Cold War, especially since they had the added vulnerability of being immigrants. But George A. Reisch has a paper on that topic in this volume which actually cites the FBI files on some of the leading positivists. Apparently, both Carnap and Philipp Frank were targets of J. Edgar Hoover's overzealous investigations.
Reisch further suggests, and I certainly agree, that this had a terrible effect on the movement. The positivists, to varying degrees,* attempted to avoid suspicion by shifting to a very austere, apolitical picture of science, totally disconnected from human values. Such a view is obviously untenable, and made the positivists much more vulnerable to the sort of criticisms Kuhn and others would make in the 60s and later.
* According to Reisch, Feigl was especially guilty of this, while Carnap stuck to his principles far more than most of the other positivists.