I have to play devil's advocate here. I reviewed "An Unfinished Conversation", and didn't think much of it. It's pretty insubstantial -- enough material for a magazine article, padded with fluff to bring it up to book length. It ignores what I consider important facets of Stan's life and times, and sanitizes his personality. (Stan was abrasive, and didn't suffer fools gladly, and his idea of who was a fool was pretty broad. I met him a few times, never had a problem, but some of my friends could tell you stories...)
It's the only biography of Stan that we have, but I wish somebody would write a more meaningful one.