I figured it would be one of those pop culture bios such as one finds in the current affairs section at Barnes and Noble -- though the Hiss-Chambers drama has not been current affairs for many, many years. But it isn't like those quickly churned-out (and frequently ghost-written) political stories.
Witness is a beautiful and terrible book. It isn't really about politics at all. It's a spiritual autobiography, about one man's placing his faith in one thing, then tearing himself away from it, and finally putting his faith in something else. The thing Chambers placed his faith in was Man -- specifically, the revolutionary hope of the mastery of Nature (including Man) by Man, which is what Communism offered. He eventually could no longer believe in Man, but dared not hope to believe in God (at least, at first).
And Chambers is not just any man. He lived an amazing life, and has the gifts to write about it. I am entranced.