While rather dated this is a nice summary of Vonnegut's novels up to and including Jailbird. This has a lot of synchronicity for me because Jailbird was the first novel of his that I purchased at the time of publication. Having been so awestruck by Slaughterhouse Five, which remains my favourite novel forty years later, I searched diligently for the earlier books (and still have them today) and it is the insights into these, especially Player Piano, which make this a very worthwhile study. I recommend it to anyone who is a Vonnegut fan (or scholar, if you insist).
This is a methodical summary of Vonnegut's writings, analysing their themes but all rather generic, brief and not particularly inciteful. It's a decent enough read, because it's short, but there's no real need to pick this up.